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A LIMNOLOGICAL STUDY OF THE FINGER LAK1 

OF NEW YORK : : By Edward A. Birge and Chancey Juday 



From 


BULLETIN 


OF 


THE 


BUREAU 


OF 


FISHERIES, 


Volume 


XXXII, 


1912 




tent No. 


79 1 












Issued October 2j, 


1014 
















WASHINGTON ,'KRNMKNT PRINTING OFK1CK 



•"Wfcfliph 



1914 



A LIMNOLOGICAL STUDY OF THE FINGER LAKES 

OF NEW YORK : I By Edward A. Birge and Chancey Juday 

From BULLETIN OF THE BUREAU OF FISHERIES, Volume XXXII, 1912 
Document No. 701 : : : : : : : : : : : : : : Issued October 27, 1014 







WASHINGTON 



GOVERNMENT PRINTING OFFICE : 



: : 1914 



0. OF D, 
NOV 2 ?914 



.FsTSs 



V 



A LIMNOLOGICAL STUDY OF THE FINGER LAKES 
OF NEW YORK 



By Edward A. Birge and Chancey Juday 

Wisconsin Geological and Natural History Survey 
Madison, Wisconsin 



52s 



CONTENTS. 

J- 

Page. 

Introduction 529 

Methods and authorities 530 

Topography and hydrography of the Finger Lakes district 532 

General account 532 

Lakes of the Seneca Basin 539 

Seneca and Cayuga Lakes 539 

Owasco Lake 540 

Keuka Lake 540 

Canandaigua Lake 541 

Skaneateles Lake 541 

Otisco Lake 542 

Lakes of the Genesee Basin 543 

Honeoye, Canadice, Hemlock, and Conesus Lakes 543 

Temperatures 546 

General observations 546 

Summer temperatures 547 

Surface and epilimnion 550 

Thermocline 551 

Hypolimnion 553 

Winter temperatures 554 

Mean summer temperatures 555 

Annual heat budget 559 

Wind-distributed heat 562 

Distribution of heat. 565 

Distribution to thermal regions 565 

Distribution to the several 10-meter strata 569 

Heat supply of the smaller lakes , 572 

Dissolved gases 576 

Methods of observation 576 

Overturning and circulation of the water 576 

Oxygen 577 

Circulation periods 577 

In the epilimnion 578 

In the hypolimnion 579 

In the thermocline 581 

Carbon dioxide 583 

Fixed carbon dioxide .. 583 

Half-bound carbon dioxide 584 

Free carbon dioxide 584 

Plankton 587 

Methods of observation 587 

Distribution of plankton organisms 588 

Phytoplankton 593 

Zooplankton 593 

Appendix. — Statistical tables ,597 

Maps facing 610 

527 



528 CONTENTS. 

INDEX TO TABLES. 

Page. 

Table I. General table of hydrography 537 

II. Areas of Cayuga and Seneca Lakes 539 

III. Summer temperatures 548 

IV. Winter temperatures 555 

V. Method of computing mean temperatures 556 

VI. Mean temperature from several series and from one 557 

VII. Mean temperatures, summer and winter 558 

VIII. Calories per square centimeter in gross heat budget 560 

IX. Annual heat budget 560 

X. Calories, Tm w to 4°, and 4 to Tm» 563 

XI. Calories of wind-distributed heat 564 

XII. Distribution of heat to thermal regions, major lakes 567 

XIII. Distribution of heat to 10-meter or 5-meter strata 570 

XIV. Distribution of heat to thermal regions, minor lakes 575 

XV. Hydrographic details of the lakes, metric system 595 

XVI. Areas and volumes of the lakes in square miles, acres, and cubic feet 599 

XVII. Temperature observations 601 

XVIII. Observations on gases 602 

XIX. Analysis of plankton catches 603 

XX. Transparency of water 609 

XXI. Oxygen table 609 



A LIMNOLOGICAL STUDY OF THE FINGER LAKES OF NEW YORK. 

By EDWARD A. BIRGE and CHANCEY JUDAY, 
Wisconsin Geological and Natural History Survey, Madison, Wisconsin. 

INTRODUCTION. 

In 1 910 the authors of this paper were enabled to visit the Finger Lakes district 
of New York, through a grant from the United States Bureau of Fisheries, and the month 
of August was spent in work upon the lakes. In February, 191 1, Mr. Juday visited 
four of the lakes to secure winter temperatures. A week in August and September, 
191 1, was used in obtaining a second set of summer temperatures. The temperatures 
of Skaneateles and Owasco Lakes were also taken in February, 1912, and in the early 
autumn of that year. 

The purpose of the investigation was to extend to these lakes the studies on dis- 
solved gases, plankton, and temperatures, which the authors had already made on the 
lakes of Wisconsin. The lakes of New York are peculiarly well adapted for such study. 
Four of those visited — Canadice, Otisco, Conesus, and Hemlock — are directly compar- 
able with several of the lakes of Wisconsin in size, depth, and biological conditions. 
The others, beginning with Owasco Lake, form a series whose smaller members are 
not greatly different from Green Lake, Wis. ; but whose largest members, Cayuga and 
Seneca, are the largest inland lakes 6 (except Lake Champlain) and the deepest in the 
United States east of the Rocky Mountains. Still further, these lakes lie in a region 
whose topography is hilly, but not mountainous. The highest elevations close to the 
lakes do not exceed 300 meters (1,000 feet) above the water, and the immediate slopes 
are, in general, much lower. The lakes, therefore, are not exposed to the peculiar 
climatic conditions of mountain lakes, but in general these conditions are comparable 
with those which exist in Wisconsin. 

Seneca Lake, the deepest in the district (188 meters, 618 feet) is much exceeded in 
depth by lakes in Europe. A score or more are found there which are comparable in 
size and form, but which reach a greater depth. Some nine European lakes exceed a 
depth of 1,000 feet. Yet Seneca Lake is so deep that from a biological point of view 
it offers conditions of life not essentially different from those of the deeper European 
lakes, and physically also it is essentially similar. These lakes are therefore directly 

a Birge, Edward A., and Juday, Chanccy: The inland lakes of Wisconsin: The dissolved gases of the water and their bio- 
logical significance. Wisconsin Geological and Natural History Survey, Bulletin xxn, Scientific Series No. 7, 259 p. 191 1. 

b It may be noted here that the term "inland lakes" is used by us in contrast to "Great Lakes," which latter name we should 
apply only to the lakes of the scries from Superior to Ontario. 

529 



530 BULLETIN OF THE BUREAU OE FISHERIES. 

comparable with the larger and deeper lakes of Europe, although such a comparison is 
reserved by us for another paper. 

There is another circumstance which makes it possible to study the Finger Lakes 
profitably. The hydrography of the six chief lakes has been determined through 
surveys made by Cornell University. These will receive more detailed notice in a later 
section. The successive classes of the College of Civil Engineering, Cornell University, 
carried on studies of these lakes almost continuously from 1874 to 1897, devoting to the 
field work a period each summer following the closing of the college year. The univer- 
sity published maps giving the outlines, soundings, and shore topography (so far as the 
last was determined) for Cayuga and Seneca Takes (scale 1 : 60,000) , Canandaigua and 
Keuka Lakes (scale 1 : 40,000) . Owasco Lake was published privately in similar manner. 
Otisco and Skaneateles Lakes have remained unpublished. Both the published maps 
and copies of drawings of the unpublished lakes have been placed at our disposal by 
Director E. E. Haskell, of the College of Civil Engineering, Cornell University, to whom 
our thanks are due for many courtesies. 

This work has had a singular fate. No limnologist appears to have made use of 
it, or, indeed, to have known of it. The volume, mean depth, etc., of the lakes can be 
determined from the data supplied by these surveys; but until the authors of this 
paper undertook the task it had not been done. The earliest survey was that of Cayuga 
Lake, begun nearly 40 years ago. It was the first to be made of an inland lake in the 
United States and antedates most similar surveys in Europe ; but it seems to be almost 
wholly unknown, as well as the surveys made later. The lakes are not mentioned in 
Murray's a account of the lakes of the world or in Halbfass's account of the lakes outside 
of Europe. 6 Yet these are the only lakes in the eastern United States which are at all 
comparable to the more important inland lakes of Europe and the surveys represent a 
quality of work which has been surpassed by only the best European surveys. 

A very careful hydrographic survey of Canadice Lake was made by the department 
of water supply of Rochester, N. Y., and the authors express their thanks for a copy of 
this map, as well as for the other courtesies rendered by the department. 

This paper represents the joint work of the authors. Mr. Juday is, however, 
directly responsible for the sections on gases and plankton and Mr. Birge for those on 
hydrography and temperatures. 

METHODS AND AUTHORITIES. 

In the account of the physical geography and hydrography c of the Finger Lakes 
the elevations above sea level are taken from the maps of the United States Geological 
Survey. The figures for the areas, depths, and slopes of the lakes are derived from the 

o Murray, J.: The characteristics and distribution of lakes. Bathymetrical survey of the fresh-water lochs of Scotland, vol. I. 
Edinburgh, 1910. 

* Halbfass, W.: Topographie, Hydrographie, Geologie der Ausser-Europaischen Seen, in Der Gegenwartige Stand der Seen- 
forschung, bd. 1, 1912. 

c Tarr, R. S.: Popular Science Monthly, vol. lxvih, p. 387-397; United States Geological Survey, Folio No. 169, p. 4, 1910. 

Watson, T. I,.: Fifty-first annual report of the New York State Museum, vol. 1, p. rs9-ni7 (1897), 1899. 

Nevius, J. N.: Ibid., p. ri3i-ris2. 

Rafter, G. W.: Hydrology of the State of New York. New York State Museum Bulletin 8s. 1905. 



A UMNOLOGICAL STUDY OF THE FINGER LAKES. 53 1 

maps of the Cornell survey for all lakes except three. Canadice Lake was surveyed by 
the Rochester water department, and no hydrographic survey has been made of Conesus 
and Hemlock Lakes. The facts regarding their area have been taken from the maps 
of the United States Geological Survey and those of depth come from the observations 
of the authors. 

The style of publication for the maps of the six lakes surveyed by Cornell Univer- 
sity was a matter that caused much hesitation. The authors would have preferred for 
many reasons to use the metric system, but they decided on the use of the foot-and- 
mile scale in order to show the shore topography by means of the maps of the United 
States Geological Survey. These topographic maps are engraved on this scale, and it 
was easy to insert the hydrography on the plates, while the cost of reengraving the 
topography on the metric scale was prohibitive. 

All of the primary measurements are based on the metric system. Each sounding 
was converted from feet to meters before being platted on the working maps. The maps 
were enlarged to twice the scale of the original or to four times that scale in cases where 
the slopes were steep and the contours crowded. The measurements of areas were 
made with great care and repeated. It need not be stated that the number of sound- 
ings, especially in Cayuga and Seneca Lakes, is not enough to insure great accuracy of 
detail in the contours; but as all of these lakes are simple, straight, narrow, steep- 
sided troughs, without islands, bays, or marked irregularities of outline or of bottom, 
the results are approximately correct, and no subsequent survey is likely to make 
substantial alterations in them. 

The contour interval of 10 meters was chosen for the primary measurements because 
of the nature of the temperature curve. The epilimnion is from 9 meters to 15 meters 
thick, and for computing temperatures the volume of the 0-10-meter zone, etc., must 
be known. In the small lakes the contour interval is 5 meters. For determining the 
volume of the several lakes the areas bounded by the several contours were measured, 
the volume of each zone was computed, and the total volume of the lakes as given in 
table 1 is the sum of the volumes of the several zones. 

In the detailed tables of the appendix the areas and volumes of the lakes are given 
in feet as well as in meters. The primary computations were all made on the metric 
system and the areas of the lakes at the 50-foot or 25-foot contour intervals were derived, 
not from the replatting of the lakes for engraving the maps, but from the hypsographic 
curves derived from the metric measurements. These areas agree essentially with those 
shown on the maps, but of course small differences appear. 

In preparing the maps for the engraver the Cornell soundings were platted on the 
outlines of the United States Geological Survey maps and the contours drawn again 
for this purpose. 

The Cornell maps are based upon a detailed survey of each lake; not only were 
the lakes sounded but their outlines were determined by a careful trigonometrical 
survey. The sounding line was of wire; an apparatus was provided for releasing the 
weight when the bottom was reached and a registering apparatus recorded the depth. 
The first machine employed is no longer in existence, but the second one, and that 



532 BULLETIN OF THE BUREAU OF FISHERIES. 

with which most of the work was done, is still in good condition. It was recently 
calibrated and found accurate. There is every reason to believe that the earlier instru- 
ment was equally good. The soundings were well placed and the position of each was 
controlled by transit instruments on shore and a sextant in the boats. Every care, 
therefore, was used to secure accuracy in detail. 

All of the under-water contours, both for the working maps and for the engraver, 
were drawn by Mr. L,. S. Smith, associate professor of topographic engineering in the 
University of Wisconsin. 

TOPOGRAPHY AND HYDROGRAPHY OF THE FINGER LAKES DISTRICT. 

GENERAL ACCOUNT. 

In the central part of the State of New York lies a plateau composed of nearly 
horizontal strata of soft Devonian shales and sandstones, whose highest points reach 
an elevation of about 700 meters (2,300 feet) above the sea. That part of this region 
with which this paper deals is known as the Finger Lakes district. (See sketch map, 
fig. 1.) It is bounded on the west by the valley of the Genesee River, which extends 
completely across the State. From this it extends about 140 kilometers (84 miles) 
eastward to the eastern tributaries of the Seneca River. It occupies the northern 
slopes of this plateau, with a maximum breadth of about 70 kilometers (40 miles). 
The meridian of 77 lies close to the center of the district, and it is bounded on the north 
by latitude 43 °. 

Lake Ontario lies about 40 kilometers (25 miles) to the north of this region. The 
district between the base of the plateau and Lake Ontario is deeply buried in drift 
whose surface is shaped into innumerable drumlins. The surface of the plateau itself 
bears but little drift. Its hills have been little eroded, but its valleys have been 
smoothed, widened, and deepened by the continental glacier. 

The waters of the western one-fifth of this district drain into Lake Ontario by the 
Genesee River, which flows almost directly north to the lake. Across the north front 
of the remainder of the district flows the Seneca River, which has its origin in Seneca 
Lake, but is continued to the west by the Clyde River and the creeks that constitute 
the headwaters of that stream. The two rivers- have a course in general almost directly 
east for 100 kilometers (60 miles) flowing between the base of the plateau region and 
the drift-covered region to the north. The stream has found out for itself a course, 
twisting about among the groups of drumlins in an imperfectly developed valley, which 
offers very little slope for its flow, so that large marshes are developed. This valley 
has furnished the course for the Erie Canal. The Seneca River empties into the Oswego 
River, which flows nearly north, directly into Lake Ontario. 

The chief tributaries of the Clyde and Seneca Rivers come from the plateau to the 
south, which is deeply trenched by their valleys. Some nine principal valleys extend 
southward into the highlands for a distance varying from 40 kilometers or less at the 
eastern and western limits to nearly 100 kilometers in the center. These valleys are 
nearly parallel. (See fig. 1.) Those in the center extend almost exactly from north to 
south. Those to the east diverge eastward and those to the west have a westward 
inclination. 



A LIMNOLOGICAL STUDY OF THE FINGER LAKES. 



533 




534 



BULLETIN OF THE BUREAU OF FISHERIES. 



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All of these valleys are 
occupied by streams. In the 
westernmost valley and in the 
second one to the east from 
thisarefoundtwoof the creeks 
that unite to form the Clyde 
River. In the easternmost 
valley is found one of the 
branches of the Onondaga 
River. The remaining six val- 
leys have been much modi- 
fied and deepened by glacial 
action and are filled in part by 
long, narrow, relatively deep 
lakes. These are the Finger 
Lakes, so called from their 
form and because they diverge 
somewhat as do the outspread 
fingers from the hand. The 
seventh lake of this series, 
Keuka Lake, occupies a 
branching valley which seems 
to have drained originally to 
thesouth. It was worked over 
by the ice in a way similar to 
the other lake-filled valleys, 
and now drains by a post gla- 
cial stream into Seneca Lake. 

The valleys occupied by 
these lakes are undoubtedly 
of preglacial origin, but they 
were profoundly altered by 
the invasion of the ice. Sen- 
eca and Cayuga Lakes extend 
below the level of the sea (see 
fig. 2) , the deepest parts of the 
Seneca Basin being 53.5 me- 
ters (180 feet) below sea level 
and those of Cayuga 16.4 me- 
ters (54 feet). These figures 
do not represent the maximum 
depth of the valleys. In the 
flat at Watkins, near the south 



A UMNOLOGICAIv STUDY OF THE FINGER LAKES. 535 

end of Seneca Lake, a boring was carried down over 300 meters (1,000 feet) without 
reaching the rock, and similar borings at Ithaca have found loose material at greater 
depths than the maximum depth of Cayuga Lake. We are not aware that any similar 
observations have been made in the other valleys. 

Between the westernmost tributary of the Clyde River and the Genesee Valley are 
four short, steep-sided valleys, deeply cut into the highlands, which here extend well 
toward the north part of the plateau. Each of these contains a lake similar in form to 
the lakes of the Seneca Basin, but much smaller and shallower than any of these except 
one. The outlets of these lakes also flow north, but soon turn west and reach the Genesee 
River by a short course. 

In this district, therefore, lie 1 1 larger lakes, each of them occupying a major valley 
in the north slope of the highlands (see fig. 1), a valley which in all cases but one opens 
independently upon the front of the highlands. The northern ends of these lakes are 
near the north end of their respective valleys and, in general, are not far from the same 
latitude. This is especially obvious in the five lakes that occupy the central and larger 
valleys. To the south these lakes extend for a longer or shorter distance in proportion 
to their length, being longer in the center of the region and shorter, in general, toward the 
east and west limits. 

In the center of this district the relatively low land of the Seneca Valley extends 
southward in a broad lobe. In the two valleys of this region lie Seneca and Cayuga 
Lakes, nearly parallel to each other and of almost exactly equal length and area. They 
are by far the largest and deepest lakes of the series. East of Cayuga and west of 
Seneca lie two other major lakes, Owasco and Skaneateles to the east and Keuka and 
Canandaigua to the west. East of Skaneateles Lake lies a single lake, Otisco, much 
smaller and shallower than any of the six; while to the west of Canandaigua come 
Honeoye, Canadice, Hemlock, and Conesus Lakes, constituting the series of four small 
lakes belonging to the Genesee Basin. 

Thus the largest, deepest, and least elevated of these lakes lie in the center of the 
group. The elevation of the surface of the lakes increases in general from these toward 
the east and the west, declining somewhat at the extreme ends of the series. (See fig. 2.) 

The lakes which lie immediately east and west of Seneca and Cayuga are similar 
in depth, though not in area. Owasco is considerably smaller than Keuka, but each is 
between 50 and 55 meters in maximum depth. The two lakes which lie next to the east 
and west, Skaneateles and Canandaigua, resemble each other very closely in length, 
area, depth, and topographic surroundings. Two lakes 70 kilometers apart can hardly 
resemble each other more closely than do these. As the table shows, they are considera- 
bly larger and much deeper than Owasco and much deeper than Keuka, although smaller 
in area. These six major lakes, in spite of their differences, belong to the same general 
class, as is shown by their dissolved gases and temperature. The small lakes lying still 
farther to the east and west are lakes of a different class, as the same series of facts will 
show. None of them reaches 30 meters in depth, and in area the largest of them is not a 
quarter the size of the smallest of the major lakes. 

The ridges between these valleys rise in general to a maximum height of about 600 
meters (1,800 to 2,000 feet) above the sea or 300 to 400 meters (1,000 to 1,500 feet) 



536 BULLETIN OF THE BUREAU OF FISHERIES. 

above the lakes. Since the lakes extend to the north ends of their respective valleys, 
where they open into the valley of the Clyde-Seneca River, the altitude of the ridges is 
in general lower at the northern end, where the valleys are also wider and the slopes of 
their sides are less steep. (See fig. 2.) To the south the valleys narrow, their sides be- 
come steeper, and the height of intervening ridges increases. These characters are most 
marked in the valleys of the larger lakes, perhaps most conspicuous of all in Cayuga 
Lake, which at one end extends deep into the highlands at the south and at the other 
reaches farthest into the valley of the Seneca River, so far, indeed, that it is continued 
to the north by the extensive marshes that bound its outlet. 

The immediate shores of the lakes are smooth and regular. They have a steep 
slope, which toward the south may rise above the lake to a height of 100 to 150 meters 
(300 to 400 feet) or more. Above this altitude this slope rises more gradually to the 
general level of the plateau, and then comes a steeper rise to the higher elevations. 
The tributary valleys on the upland slopes are broad, and the lower and steeper slopes 
are trenched by innumerable narrow gorges. These range in size from gullies which serve 
to carry off the rains, but are usually dry, to picturesque gorges, cut deep into the rocks 
and occupied by considerable streams. Of these last the most famous are Watkins Glen 
at the south end of Seneca Lake and the several gorges at the south end of Cayuga Lake. 

The smoothly outlined shores of these lakes show few irregularities or decided 
projections except where the axis of the lake bends on account of the course of the 
original valley. Long Point on Seneca Lake is an instance of such a structural pro- 
jection. Cayuga Lake has a broad expanse of shallow water at the north end, and 
here there are several points and one small island (the only island in the series of lakes) 
which represent irregularities of the original shore. The maps show similar conditions 
in less marked degree at the north end of other lakes. In general, however, the irregu- 
larities of the water line are small and are due to flat deltas and spits built by the 
tributary streams and by the waves. These constitute a characteristic and very beautiful 
feature of the shores of the lakes. They vary greatly in size according to the drainage 
basin of the stream that produced them. The maps of the lakes show numerous examples 
of such points; Myers Point on Cayuga Lake is perhaps the largest; and the flat on the 
west side of Seneca Lake on which the town of Dresden is situated was built in similar 
fashion by the outlet of Keuka Lake. In Conesus Lake (fig. 3) two such points opposite 
each other near the middle of the lake have nearly divided it. 

The form of the lakes and their steep banks have so directed the course of the 
winds that very little work has been done by the waves along their sides. As a result, 
the wave-cut shelf is very narrow and the water deepens close to the shore and very 
rapidly. Few large tributaries enter the lakes by their sides ; most of the larger streams 
enter at the south end. (See fig. 1.) 

The larger lakes of the Seneca Basin take in and give out during the year an amount 
of heat whose aggregate is enormous. It has been computed that this is equal to the 
heat generated by the combustion of nearly 150,000 tons of coal for each square mile 
of the surface of the lake. The total amount of heat from Seneca Lake would equal 
that from nearly 10,000,000 tons of coal. This heat is absorbed by the water in the 



A UMNOLOGICAL, STUDY OF THE FINGER LAKES. 



537 



spring and liberated in autumn and produces a considerable local effect on the climate. 
The effect is intensified by the narrow valleys with their steep slopes which concentrate 
and localize the influence of the water. Frosts are delayed in autumn, and in spring 
the cold water chills the air of the valleys so that vegetation does not start until the 
danger of killing frosts has passed. The slopes of the lake basins are therefore peculiarly 
well adapted for raising fruit, and many orchards and vineyards are found there. The 
steep shores of Keuka Lake, especially, are covered with vineyards, as thick set as those 
of the Rhine. 

The Finger Lakes comprise a group of n neighboring lakes, similar in form and 
topographic situation but differing widely in area and depth. Six of them may be 
classed as major lakes and five as minor, although the lakes in each group differ greatly 
from each other. The series offers for study lakes whose range of length is from 5 
kilometers to more than 60 kilometers and whose range in depth is nearly tenfold. Thus 
the series extends from lakes of quite ordinary character to those which are inland lakes 
of the first order in every sense of that term. It is probable that there is no group of 
lakes in the world which offers to the limnologist such opportunities for working out 
the problems of his science. 

Table 1 gives the general facts of the hydrography for the several lakes and for 
Green Lake, Wis., which is frequently compared with the New York lakes in the dis- 
cussion of temperatures. 

Table I. — Hydrography of the New York Lakes. 



Lakes. 















Breadth. 






Drainage area. 


Elevation 


Length. 
















A 














Maximum. 


Mean. 




Square 


















Square 


kilo- 


Square 






Kilo- 




Kilo- 




Kilo- 


kilo- 


meters. 


miles. 


Meters. 


Feet. 


meters. 


Miles. 


meters. 


Miles. 


meters. 


meters. 


31 


12 


333 


1,092 


5.1 


3-2 


0.62 


o.39 


0.51 


2.6 


453 


I7S 


209 


686 


24.9 


IS- 5 


2.44 


1.50 


1.70 


42.3 


2,106 


813 


116 


381 


61.4 


38.1 


5.60 


3-So 


2.80 


172.1 


231 


89 


249 


818 


12.6 


7.8 


1.34 


•83 


1.06 


13.4 


111 


43 


273 


896 


10.8 


6.7 


.80 


.50 


.70 


7.2 


484 


187 


216 


709 


31.6 


19.6 


3.32 


2.06 


1.15 


47.0 


88 


34 


239 


784 


8.7 


5-4 


1.22 


.76 


.89 


7.6 


539 


208 


217 


710 


17.9 


11. 1 


2.10 


1.30 


1.49 


26.7 


' 1,831 


707 


135 


444 


56.6 


35-1 


5.20 


3-25 


3.10 


175.4 


189 


73 


264 


867 


24.2 


15-0 


2.35 


1.46 


1.48 


35.9 


246 


95 


275 


902 


11.9 


7-4 


3.22 


2. 00 


2.50 


29.7 



Canadice 

Canandaigua 

Cayuga 

Conesus 

Hemlock 

Keuka 

Otisco 

Owasco 

Seneca | 1,831 

Skaneateles 

Green (Wis.) 



Square 
miles. 

i. o 
16.3 
66.4 

5-2 

2.8 
18. r 

2.9 
10.3 
67.7 
13-9 
II- S 



Lakes. 



Depth. 



Maximum. 



Mean. 



Dm. 



Dmx. 



Volume. 



Mean slope. 



Development. 



Shore. Volume. 



Canadice. . . , 
Canandaigua 

Cayuga 

Conesus 

Hemlock .... 

Keuka 

Otisco 

Owasco 

Seneca 

Skaneateles . 
Green (Wis.) 



Meiers. 
25.4 
83.5 

132.6 
18.0 
27.5 
55.8 
20.1 
54.0 

188.4 
90.5 
72.2 



Feel. 

83 
274 
435 

59 

90 
183 

66 
177 
618 
297 
237 



Meiers. 
16.4 
38.8 
54.5 



0.65 
.46 
.41 



Million 
cubic 
meters. 
42.6 
1,640.1 
9,379.4 



30.5 
10.2 
29.3 
88.6 
43.5 
33.1 



•55 
■51 
■54 
•47 
.48 
.46 



1,433.7 

77.8 

780.7 

15,539.5 

1, 562. 8 

984.8 



Million 

cubic feet. 

i>5°3 

S7>897 

33i>o8o 



Per 

cent. 

6.2 

7.0 

5.2 



50,610 
2,746 
27,578 
548, 544 
55.ISI 
34.751 



7.8 
2.3 
4.4 
9.0 
8.4 
5.4 



3 33 

4 
2 58 



2.05 
2.48 
3-35 



1.04 
1-30 
'■ 23 



4-5* 
2.04 
2.27 
2-74 
2.45 
1.7$ 



1-64 
'■52 
1.63 
I. 41 
1.44 
r.3« 



538 



BULLETIN <DF THE BUREAU OF FISHERIES. 
Table I. — Hydrography of the; New York Lakes — Continued. 



Lakes. 


A. 

2 

atM. 


Per cent 
of Dm. 


y 

2 

atM. 


Per cent 
of Dmx. 


Surveyed by- 


Date. 


Number 
of sound- 
ings. 


Scale of 

original 

map. 


Canadice 


19- S 
44.0 
47- 


77 
53 
33 


9-5 
26.0 
40.0 


37 
31 
30 


City of Roches- 
ter. 

Cornell Uni- 
versity. 

do 

U. S. Geolog- 
ical Survey. 

do 


1909 

1888-1890 

1873-1878 
1904 

1904 

1884-1888 

1897 

1896-97 

1878-1883 

1893 

1898 


283 
39S 
397 


1:2,400 

1 140,000 




Cayuga 




















Keuka 


32-0 

12- 5 

33- 
88.0 
46. 

32-0 


62 
61 
47 
51 
44 


18.0 

6.6 
18.0 
57-0 
29.0 
23.0 


32 

33 
33 
30 
32 
32 


Cornell Uni- 
versity. 

do 

do 

do 

do 

Wisconsin 
G e 1 ogical 
Survey. 


47o 

144 
276 
4°S 
572 
697 


1 :4c 000 


Otisco 


Owasco 




Seneca 








Green (Wis.) 









EXPLANATION OF TABLE I. 

In table 1 the areas of drainage basins were taken from Rafter's Hydrology of New York, except Canadice Lake, whose 
basin was measured from United States Geological Survey maps, and Green Lake, which was measured from Wisconsin maps. 

The drainage area of Seneca Lake includes that of Keuka Lake. 

Elevations above sea were from the United States Geological Survey maps, except Green Lake. In this case the elevation 
is that found in Gannett's Dictionary of Altitudes in the United States, and refers to the railway station, which is somewhat 
below the level of the lake. 

Length, depth, etc., were measured or computed from the maps named in the table. 

The length of each lake was measured along its axis. That given for Keuka Lake is the length of the east arm and main 
lake; the west arm is 10.6 kilometers (6.6 miles) long. The maximum breadth of Keuka Lake is at the junction of the arms; 
elsewhere the maximum breadth is 1.48 kilometers (1.1 miles). 

The mean breadth of the lakes was found by dividing the area by the length. The mean depth was found by dividing the 
volume by the area. 

The depths given for Hemlock and Conesus Lakes are those found by the authors. The lakes have not been surveyed, but 
probably these numbers are near the maximum depth. 

j=r— — is the ratio of the mean depth to the maximum depth. 

The volume assigned to each lake in this table is the sum of the volumes of the several strata as given in the tables of detailed 

(A+B+VAB) 



- , in which h is the contour interval, A and B 



H (*Alo+h + h+ + Zn-I + M/n) 



, in which H 



hydrography (p. 597). These are computed from the formula a = A 
are the areas of the bounding planes of the stratum. 

The mean slope was computed according to the formula of Gravelius «S = 

is the depth of the lake, A its area, and U, h, etc., the length of the successive contours. 

The mean slope of the areas between the several contours in the detailed tables of hydrography was calculated from the 

formulaS= - 7 r, in which h is the contour interval, a the area between the contours, and h, h the length of the contours. 

0(2) 

Shore development is the ratio of the perimeter of the lake to the circumference of a circle whose area equals that of the lake. 

Volume development is the ratio of the volume of the lake to that of a cone whose base equals the area of the lake and whose 

height is the maximum depth of the lake. If the sides of the lake were vertical the volume development would be 3 or the 

volume would be that of a cylinder of equal base and altitude. The formula is = and the numbers of this column are there- 

Dmx 

fore three times those in the column ic . That part of the number which follows the decimal point is, in these lakes, the same 

Dmx 

as Peucker's figure for "mittlere Wolbung." 

— at m. This column shows to the nearest meter or half meter the depth at which the area cf the lake basin is reduced to 
2 

one-half of that of the lake's surface. 

V 

— at m. shows in like manner the depth of the plane which divides the volume of the lake into two equal parts. 

2 

The columns headed "per cent of Dmx" show the ratio of these depths to the maximum depth of the lakes. 
See account of Otisco Lake (p. 542) for other statistics. 



o Gravelius, H.: Die mittlere Boschung. Zeitschrift fur Gewasserkunde, bd. ix, p. 267. 



A EIMNOLOGICAL, STUDY OF THE FINGER LAKES. 539 

LAKES OP THE SENECA BASIN. 

Seneca and Cayuga Lakes (pi. cxiii, cxiv). — These are the largest and deepest lakes 
of the group and closely resemble each other in surface dimensions. Seneca Lake, how- 
ever, is nearly 56 meters deeper than Cayuga, the ratio of the maximum depths of the 
two lakes being 1 : 1.42. The mean depth of Cayuga Lake is even less, being to that of 
Seneca in the ratio of 1 : 1.63, and their volumes have about the same ratio. The map 
shows a large area of shoal water at the north end of Cayuga Lake, which is not found 
in Seneca Lake. The outlet of Cayuga Lake, also, passes at once into the extensive 
Montezuma marshes, another indication of the flat condition of the country at the 
north end of the lake. 

The topography of the shores of these lakes is very similar. The country is relatively 
flat at the north end. (See fig. 2 as well as the plates.) The shores rise toward the 
south and for the southern half or two-thirds of their length, the lakes are bounded by a 
steep slope, often precipitous at the bottom, which reaches in places 100 meters or 
more in height. Above this steep slope there is for much of the way a more or less 
definitely marked shelf, and above this there is another rise to more considerable isolated 
heights. There are no high hills which crowd down toward the water as is the case in 
most of the other lakes. The lakes have the appearance of a broad, quiet river, with 
steep banks of nearly uniform height. Their scenery is therefore rather tame as com- 
pared with that of the other major lakes; but at the southern end of both lakes the 
entering streams have cut deep gorges which are famous for their beauty. The lateral 
tributaries of these lakes are larger than those of the smaller ones and points built out by 
them into the lakes are correspondingly larger. At the south end of each of these lakes 
there is a flat or delta built out into the water by the large streams which enter from the 
south. 

The authorities which we have consulted give the area of Cayuga Lake as slightly 
larger than that of Seneca, but our very careful measurements, both from the Cornell 
maps and those of the United States Geological Survey, reverse this relation. The 
following table shows the details for each lake : 

Table II. — Areas of Cayuga and Seneca Lakes. 





Authority. 


Area in square miles. 




Cayuga. 


Seneca. 




66.8 
66.4 
66.0 


66.0 




67-7 
66. j 







" Rafter, G. W.: Hydrology of the State of New York. New York State Museum Bulletin 85, 1905, p. 216. 

The transparency of these lakes, as measured by Secchi's disk in 1910, was 5.1 
meters for Cayuga Lake and 8.3 meters for Seneca. 

These lakes are part of the canal system of New York, and their outlets are 
controlled by the works at the entrance of the canals into the lakes. 
46512°— 14 2 



54-0 BULLETIN OF THE BUREAU OF FISHERIES. 

Our observations on Seneca Lake were made in the deep water off North Hector. 
In Cayuga Lake they were made off Sheldrake and King Ferry. 

For the details of the hydrography, see p. 598. 

Owasco Lake (pi. cxn). — Owasco Lake is the smallest of the six major lakes, having 
about 70 per cent of the length of Skaneateles and Canandaigua Lakes. Its mean 
breadth is, however, somewhat greater, so that its area is about 70 per cent of that of 
Skaneateles Lake, its neighbor to the east. It is also the shallowest lake (54 meters, 
177 feet), although Keuka Lake exceeds it by less than 2 meters in maximum depth, 
and a little more than 1 meter in mean depth. It has the form typical of these lakes — 
a broader, rather shallow northern part extending into the lower country, and a narrow 
south part with steep sides. The valley, however, lies in that depression of the high- 
land which includes the north parts of Seneca and Cayuga Lakes. Its banks are, 
therefore, on the whole, lower than those of any of the other lakes, although of the same 
general character. The valley extends about 30 kilometers (18 miles) to the south, 
and with steeper slopes than any of those found immediately adjacent to the water. 
Near the lake the steep slope at the bottom never exceeds 100 meters, and is usually 
much less, and above this the slopes are gradual and do not rise to elevations much 
exceeding 200 meters above the lake. The lake itself is about 100 meters above Cayuga 
Lake, its neighbor to the west, and less than half as much below Skaneateles Lake. 

The outlet is controlled by a dam, and the lake is the source of water supply for 
the city of Auburn, which lies at its north end. The south end of the lake is somewhat 
silted up by alluvium brought down by the inlet, as is shown by the form of the 25-foot 
contour, and the valley is probably deeply filled with loose materials. 

In a report made in 1909 to the city of Auburn, Mr. G. P. Whipple computed the 
volume of Owasco Lake as equal to about 200,000,000,000 gallons, which would equal 
about 2,670,000,000 cubic feet. This computation is based on the same survey as ours, 
and is somewhat smaller than our estimate. (See table 1.) Whipple's diagram, how- 
ever shows the volume of the lake as slightly larger than our figures. 

Our observations in 1910 were made off Wyckoff, and temperatures were taken 
there in the winters of 191 1 and 191 2. Four series of temperatures were taken in 191 1, 
the first near Rice Point at the south, and the last near the northern limit of the 
100-foot contour. 

For the details of the hydrography, see p. 598. 

Keuka Lake (pi. cxv). — Keuka Lake, which drains into Seneca Lake, lies about 
80 meters above it. The stream which carries its water flows through a narrow post- 
glacial gorge and empties into Seneca Lake near Dresden. 

Keuka is the largest of the lakes after Cayuga and Seneca, and it is also the 
narrowest. It is the only lake whose outline is irregular. Its west arm, though the 
shorter, is the deeper, the 150-foot contour extending close to the northern end. The 
lake lies, as a whole, farther to the south than does any other of the district, and both 
branches of the basin are narrow to the extreme north end, since the valley does not 
widen out on the northern face of the plateau. It is one of the shallowest of the six 
major lakes, being less than 2 meters deeper than Owasco. The under-water slopes of 



A UMNOLOGICAL STUDY OE THE FINGER LAKES. 541 

the basin are very steep, as are also those above water; and these steep slopes begin 
close to the northern end of the lake and extend through its length. Bluff Point, which 
divides the two arms of the lake, is one of the finest hills to be found adjacent to the 
lakes, and has been most characteristically shaped by glacial action. 

The waters of Little Lake, which is shown on the map, drain into the Susquehanna 
River, and thus reach Chesapeake Bay, while those of Keuka Lake ultimately reach 
the Gulf of St. Lawrence. 

Observations were made on Keuka Lake in the deepest water off Grove Springs. 

For the details of the hydrography, see p. 598. 

Canandaigua Lake (pi. cxvi). — Canandaigua Lake repeats the typical form of the 
Finger Lakes — a basin, relatively broad and shallow at the north end, with flat low- 
lying shores. To the south the hills rise and steepen and come down close to the lake. 
The hills on the east side rise with a steep slope almost to their summits, South Hill 
showing a rise of nearly 400 meters in 1 kilometer, while other slopes are nearly as 
steep for shorter distances. No lake has so many high hills adjacent to it. Burr and 
South Hills lie to the east, and on the west are Powell and Stid Hills. Between these 
is Bristol Hill, which reaches a height of about 500 meters (1,604 feet) above the lake. 
Its summit is just to the west of the limits of the map, due west from Lapham Point. 
Between these hills are deep valleys, of which Vine Valley on the east side is the most 
conspicuous. These high hills, with their valleys, make the scenery of Canandaigua 
Lake more diversified than that of any other Finger Lake. No single view, indeed, is 
finer than that of Bluff Point from Keuka Lake, but in variety of scenery Canandaigua 
excels. 

The transparency of the lake in 1910 was 3.7 meters, the lowest found in the major 
lakes. 

Observations on gas and plankton were made in the deepest water and not far from 
Grange Landing. In both 191 1 and 191 2 four series of temperatures were taken, of 
which the southern was near Cooks Point, and the northern near Hope Point. 

For the details of the hydrography, see page 597. 

Skaneateles Lake (pi. cxi). — Skaneateles Lake is the easternmost of the six major 
lakes and is almost a replica of Canandaigua, the westernmost. Its length is almost the 
same, its breadth slightly less, and its area correspondingly smaller. Its depth, both 
mean and maximum, is greater, in spite of which the shores to the south are not so high 
as those of Canandaigua, nor are there the deep lateral valleys that diversify the steep 
walls of the latter basin. The highest and steepest slopes are reached only at the 
extreme south end of the lake and extend up the valley beyond the water. Here on 
the west side is found a slope about 250 meters high with a gradient of about 1 13. This 
is, as usual, exceeded by the under-water slopes, which reach near Carpenters Point a 
maximum of 1:1.5 for a height of 60 meters. 

The transparency of the lake in 1910 was 10.3 meters, by far the greatest found. 
This had no apparent effect on the distribution of temperature. 

Skaneateles Lake serves as a reservoir for part of the canal system of New York, 
and its outlet is controlled by a dam, which raises the water perhaps about 2.5 meters 



54 2 BULLETIN OF THE BUREAU OF FISHERIES. 

(8 feet) above its natural low level of 70 years ago. The water of this lake, with that 
from Otisco Lake, is also used for the water supply of the city of Syracuse, which lies 
some 27 kilometers to the northeast. 

Our observations in 1910 were made off Carpenters Point. The later temperature 
observations were taken off Mandana. 

For the details of the hydrography, see page 599. 

Otisco Lake (pi. cxi). — Otisco Lake is quite similar in situation and form to the six 
major lakes, but is wholly different in area, depth, and biological character. The lake 
is used as a source of water supply for the city of Syracuse, which lies about 27 kilo- 
meters to the northeast. The height of the water is controlled by a dam, which may 
raise the water 3 meters or more above its original level. This dam is placed some 1.5 
kilometers below the original outlet and has thus caused a shallow extension of the 
lake at the south end. The sides of the original lake are steep, and the increase in height 
of the water adds little to its breadth. At the south end of the lake the floor of the 
valley slopes very gradually and here the dam has caused a broad, shallow expanse 
which varies greatly in area with the rise and fall of the water as it is drawn upon for 
the use of the city. 

Across this shallow expanse and close to the original south end of the lake there runs 
a causeway pierced only by a narrow opening. There is thus a considerable area of 
shallow water which is practically separated from the main body of the lake. 

In the general table of the lakes the statistics for Otisco Lake are based on the 
Cornell survey and include the entire lake. The level of the water shown by this survey 
was not correlated with the level of the crest of the dam, or if such measurements were 
made (as they probably were) the records have disappeared. The water was probably 
about 1 meter below the spillway at the time the soundings were taken. They there- 
fore do not represent the maximum possible depth of the lake, but are probably quite 
as great as the ordinary depth. 

For all purposes of limnology the southern extension of the lake beyond the cause- 
way has no significance, however valuable it may be as a storage for water supply. 
For the purposes of our discussion, the dimensions of the lake must be recalculated, 
including that part of the lake which lies between the dam and the causeway. The 
results are as follows: Length, 7.33 kilometers; breadth, maximum, 1.22 kilometers; 
mean, 0.93 kilometers; area, 6.84 square kilometers; depth, maximum, 20.1 meters; 
mean, 11. 2 meters; volume, 76,440,000 cubic meters; shore development, 1.76; volume 
development, 1.64; mean slope, 2.41 per cent, i° 23'. These measurements are 
employed in the table of hydrography, page 597. 

Otisco Lake occupies only a small part of its valley, which extends far beyond the 
lake both to the north and the south. Its steepest slopes begin at about the same 
point as do those of the Skaneateles valley, and since the lake is little more than one- 
third as long, they lie wholly to the south of the water. In general they are more 
broken and diversified than are those of the other eastern lakes. There is hardly a 
view in this picturesque and beautiful region finer than is that which the Otisco Valley 



A UMNOLOGICAIv STUDY OF THE FINGER LAKES. 543 

offers as the traveler from Skaneateles first enters it from the south, high up on the slopes 
of its western side. 

Otisco Lake was visited only once. The work was done off Amber, in the deepest 
water. The lake abounds in plankton, as is indicated by the absence of oxygen and 
plankton in the deeper water. Its transparency in ioiowas 3 meters, the least shown 
by any of the lakes, but not much less than several of them. 

For the table of hydrographic details, see page 597. 

LAKES OF THE GENESEE BASIN. 

Honeoye, Canadice, Hemlock, and Conesus Lakes (fig. 3). — These four small lakes 
lie to the west of Canandaigua Lake (fig. 1), in narrow valleys, at an average altitude 
decidedly greater than that of the lakes of the Seneca Basin (fig. 2). One of them, 
Honeoye Lake, was not visited by us. The lake is shallow, as is shown by the large 
deltas which have been built out into it by the small streams along its sides. 

Conesus, the westernmost lake, lies farthest to the north, and therefore comes 
nearest to the mouth of its valley. The valley is shallow and has gradual slopes, not 
exceeding 1:5 for a height of 100 meters (over 300 feet). The highest hills adjacent 
to the lake do not reach a height greater than 160 meters (530 feet) above its surface. 
The most interesting topographic feature of the lake is the fact that near its center 
two streams, entering opposite each other, have built out large deltas, which have nearly 
divided the lake. The water is shallow; we found no depth greater than 18 meters. 
We made soundings along the center of the southern half of the lake, and the greatest 
depth of the lake is probably little, if at all, greater than that found by us. The trans- 
parency of the water was 6.3 meters, which was exceeded only by Skaneateles and 
Seneca Lakes. The oxygen and plankton of the lake show the regular characters 
that belong to a shallow lake. 

Canadice and Hemlock Lakes lie close together in the center of this group. They 
are separated by the height of Bald Hill, which lies between them, much as Bluff Point 
lies between the two arms of Keuka Lake, and which has a form quite similar to that 
of Bluff Point (pi. cxv). It rises, however, to a greater height, since its summit is 
nearly 600 meters (1,850 feet) above the sea, and it rises more than 230 meters (760 
feet) above Canadice Lake and about 290 meters (950 feet) above Hemlock Lake. 
The water of these two lakes furnishes part of the supply for the city of Rochester, 
which lies about 45 kilometers (28 miles) to the north. 

Hemlock Lake is long, narrow, nearly straight, and is singularly uniform in 
breadth. The walls of the valley are steep, the steepest slopes rising 300 meters or 
more in 1 kilometer. None of the slopes are precipitous, but many of them are about 
as steep as is possible for a wooded slope to lie. Marrowback Hill, on the west of the 
lake, is as steep as Bald Hill on the east and reaches a height some 30 meters (100 feet) 
greater. The sides of both these hills are uniform and are unbroken by valleys or 
projections. Toward the north end of the lake are a few small streamlets whose val- 
leys are almost invisible, and even these are not found along the southern two-thirds 



544 

T7"OS 



BULLETIN OF THE BUREAU OF FISHERIES. 

7T"SS' 




4SJO 



4&S' 



KW' 



r#t>" i> > s.c.s /*■"> 



Fig. 3.— Contour map of western lakes of the Genesee Basin from topographic sheets of the United States Geological Survey. 
Scale about 1: 155,000; 1 inch=2.s miles; 1 cm.=i.6 km. Contour interval 100 feet. Elevations in feet above the sea level. 
Numbers on tops of hills indicate highest contoitr shown on United States Geological Survey map. The height between 
Canadice and Hemlock Lakes is Bald Hill; that west of Hemlock Lake is Marrowback Hill. 



A LIMNOLOGICAI, STUDY OF THE FINGER LAKES. 



545 



of the lake. There are, therefore, no deltas built into the lake, but the steep wall of 
the valley rises immediately from the water on both sides of the lake. 

The outlet of Hemlock Lake is controlled by a dam, which may raise the water to a 
height of about 1.6 meters (5 feet) above its natural level. No hydrographic survey 
has been made of the lake. This is the more regrettable since the form and topography 
of the lake adapt it admirably to the study of the temperature seiche. Not only is 
the lake straight and of uniform breadth and depth, but the shape and depth of the 
valley are such that all winds that affect the water must blow parallel to the long axis 
of the lake. 

The maximum depth of the lake as found by us was 27.5 meters (90 feet), and this 
was said by the officials of the Rochester water department to be the deepest water 
of the lake. The observations on Hemlock Lake were made near the middle of its 
length. 

The transparency in 1910 was 4.7 meters. 




Fig. 4. — Hydrographic map of Canadice Lake. From survey by city of Rochester department of water supply. Contour 
interval, 25 feet. Scale, about 1: 64,000. Note the steep sides and flat bottom of the lake. The outlet of the lake is at the 
north end. 

Canadice Lake (fig. 4) is the smallest of the lakes which we visited and the only 
lake of the Genesee Basin which has had a hydrographic survey. This was done with 
great care by the department of water supply of the city of Rochester, whose officials 
were so kind as to place their maps at our disposal. 

The valley of Canadice Lake is a simple trough, with smooth steep walls, almost 
exactly like the valley of Hemlock Lake, though the eastern slopes of Canadice Valley 
carry somewhat larger streams and have cut somewhat deeper into its sides. The slopes 
under water are even steeper than those above it and the ratio between the maximum 
and the mean depth of the lake (see table 1) is considerably greater than for any other 
lake. More than three-fourths of the maximum depth must be passed before the plane 
is reached whose area is one-half that of the surface. In correspondence with this 
relatively great depth and volume Canadice Lake shows a biological character more 
resembling that of the larger lakes than does any other of the smaller lakes. It carries 
a good deal of oxygen to the bottom. The temperature of the deep water is low in 
spite of the fact that its total gains of heat are higher than would be expected from its 
area. 

The lake was visited once and observations were made near the north end. The 
transparency of the lake was 4 meters. 

For the details of the hydrography of the lake, see page 597. 



546 BULLETIN OF THE BUREAU OP FISHERIES. 

TEMPERATURES. 

GENERAL OBSERVATIONS. 

Temperature observations were made in these lakes on the following dates: 

Lake. Date of observations. 

Canadice Aug. 24, 1910. 

Canandaigua Aug. 20, 1910; Sept. 4, 1911. 

Cayuga Aug. 11, 1910; Feb. 13, Sept. 2, 1911. 

Conesus Aug. 25, 1910. 

Hemlock Aug. 23, 1910. 

Keuka Aug. 18, 1910; Sept. 5, 1911. 

Otisco Aug. 16, 1910. 

Owasco Aug. 13, 1910; Feb. 11, Sept. 3, 1911; Mar. 1, Sept. 13, 1912.0 

Seneca Aug. 2, 3, 4, 7, 9, 1910; Feb. io, Sept. 1, 1911. 

Skaneateles Aug. 15, 1910; Feb. n, Sept. 3, 1911; Mar. 7, Oct. 15, 1912." 

The details of the observations are given in the tables of the appendix (p. 601). It 
will be seen that in all of the lakes temperatures were taken in August, 1910, and in four 
of the lakes series of temperatures were taken only at that time. Two other lakes were 
visited also in early September, 191 1. Four others were visited in both summers and 
in February, 191 1, and two of these also in March, 191 2, and in the fall of that year. 
The attempt was made to secure series of temperatures which would show approximately 
the maximum summer temperature of the water, and in the case of those visited in the 
winter, the minimum temperature also. The most important conclusions to be drawn 
from the observations, as will be shown later, concern the annual heat budget of the 
lakes and the distribution of the heat in summer. 

The study of the New York lakes was made in order to test in larger bodies of water 
the principles of lake temperatures established for the inland lakes of Wisconsin. Since 
the phenomena of the Finger Lakes exactly- conform to these principles, we have not 
hesitated to use them as illustrations of these laws, though we should not have deduced 
the laws from them alone. The full discussion of these underlying principles belongs 
to the report on lakes of Wisconsin now under preparation, but several of them are 
briefly discussed in connection with this report. 

The following principles are therefore assumed as demonstrated for lakes in the 
general climatic and topographic situation of the Finger Lakes. It is not asserted that 
they hold for lakes situated under other conditions. 

1 . Every deeper lake has an equithermal period of several weeks in summer, cover- 
ing as a maximum August and parts of late July and early September, during which 
the daily gains and losses of heat nearly balance, when the mean temperature of the lake 
is substantially constant, and when the epilimnion has a nearly constant thickness. A 
series of observations taken on one day during this period gives a good idea of the 
general temperature condition of the lake during the whole period. 

The observations of 1912 were made by Mr. J. W. Ackermann, superintendent of water works, Auburn, whose kind assist- 
ance is herewith acknowledged. 



A UMNOLOGICAL STUDY OF THE FINGER LAKES. 547 

2. This condition recurs annually, unless under extraordinary conditions of weather, 
and the annual differences are not great enough to invalidate or seriously weaken general 
conclusions based on a single year. 

3. A series of temperature observations taken in summer under good conditions of 
weather, and near the center of oscillation of a lake of regular form, gives a fair idea of 
the mean temperature of the water of the lake. 

4. In lakes of this type, all heat gained which is above 4 and which is found below 
a depth of 5 meters, has been conveyed there by mechanical agencies; by currents due, 
directly or indirectly, to wind. Such heat may be called wind-distributed heat. The 
same is true of most of the heat found between the depth of 1 meter and 5 meters. There 
is as yet no clear evidence that thermal convection currents aid appreciably in carrying 
heat downward. 

5. The thickness of the epilimnion in lakes of different size and otherwise comparable 
is a fair measure of the relative efficiency of the wind in distributing heat. 

SUMMER TEMPERATURES. 

As a result of the normal conditions of weather acting on the lake, it divides in 
summer into three well-known thermal regions. 

1. The epilimnion, a stratum in which the temperature is nearly uniform. The 
surface is usually the warmest part of the stratum. Under summer conditions the fall 
of temperature in this region varies from a small fraction of a degree to several degrees. 
The amount varies chiefly with the temperature of the surface and is therefore subject 
to diurnal variation. It is greatest in the afternoon of a hot, calm day; least in the early 
morning, when the surface may be cooler than the stratum immediately below it. 

2. The thermocline, the stratum of rapid cooling, whose limits are somewhat arbi- 
trarily fixed as those of the region in which the fall of temperature equals or exceeds 
1 degree per meter. Its upper limit is usually fairly definite, but below it grades off 
into the third region and its lower limit is often somewhat arbitrary. From 60 to 70 
per cent, or even more, of the fall in temperature is usually found here. The thermo- 
cline is subject to variation in thickness under the action of wind and of oscillations due 
to temperature seiches. At the center of the lake where these influences are least felt, 
it is still subject to oscillations of considerable amount. These may cause an increase 
or decrease of the thickness of the thermocline, and at its bottom isotherms may be 
drawn in or excluded by its extension or contraction. 

3. The hypolimnion, the region below the thermocline and extending to the bottom 
of the lake. In this region the temperature falls slowly, the temperature curve soon 
approaching a straight line. The amount of fall in this region varies greatly according 
to the conditions of the spring warming. It may be less than 3 , even in a layer more 
than 60 meters thick, or it may be as much as 6°. It may be as little as 1 1 per cent of 
the total fall in temperature or it may be nearly 40 per cent. 



548 



BULLETIN OF THE BUREAU OF FISHERIES. 

Tabi,e III. — Summer Temperatures op the New York Lakes. 





Year. 


Depth. 


Temperature. 


Epilimnion. 


Lakes. 


Surface. 


Bottom. 


Fall of 
tempera- 
ture. 


Thick- 
ness. 


Fall of 
tempera- 
ture. 


Percent 

of total 

fall. 


Fall per 
meter. 




1910 
1910 
1911 
1910 
1911 
1910 
1910 
1910 
1911 
1910 
1910 
1911 
1912 
1910 
1911 
1910 
1911 
1910 
1911 
1912 


Meters. 
2S-4 
8S-S 


°C. 

22.2 
21.7 
20.7 
19.8 
20.0 
21.8 
22.0 
21.2 
20.6 
23.0 
21.5 
19.8 
19.6 
20.0 
20.0 
22.7 
19.6 
22.5 
20.5 
21.7 


°C. 
8.0 
5.4 
4.3 

4.4 
4.1 

12.5 
9.3 
6.4 
4.8 

12.0 
7.0 
5.3 
7.3 
4.2 
4.0 
5.4 
4.4 
5.3 
5.8 
6.3 


"C. 

14.2 
16.3 
16.4 
15.4 
15.9 
9.3 
12.7 
14.8 
15.8 
11.0 
14.5 
14.5 
12.3 
15.8 
16.0 
17.3 
15.2 
17.2 
14.3 
15.4 


Meiers. 
7 
12 
12 
IS 
16 
8 
8 
9 
II 
7 
12 
12 
IS 
12 
IS 
9 

11 
14 
10 


°C. 

0.4 
2.0 
2.4 

.6 
1.4 

.4 

.3 
1.9 
1.1 
1.0 
2.0 

.3 
1.4 
2.0 
1.6 
3.7 

.8 
2.0 
1.0 
1.2 


2.8 
12. 2 
14.6 
3-9 
8.8 
4-3 
2.4 

12.8 

7.0 

Q.I 

13-8 

2-7 

11. 4 

12. r 
10. 

21. 4 

5-3 
11. 6 
7.0 
7-8 


°C. 
0.06 




.17 


Do 


.20 




132-6 


.04 


Do 


.09 
.05 




18.0 
27-3 
5S-8 




.04 




.21 


Do 


.10 




20. 1 
54- 


.14 




.17 


Do 


.02 


Do 




.93 




188. 4 


.17 


Do 


.11 




90. s 


.41 


Do 


.05 


Green (Wis.) 


72. 


.18 


Do 


.71 


Do 




.12 









Lakes. 



Canadice .... 
Canandaigua 

Do 

Cayuga 

Do 

Conesus 

Hemlock 

Kenka 

Do 

Otisco 

Owasco 

Do 

Do 

Seneca 

Do 

Skaneateles . 

Do 

Green (Wis.) 

Do 

Do 



1910 
1910 
1911 
1910 
1911 
1910 
1910 
1910 
1911 
1910 
1910 
1911 
1912 
1910 
1911 
1910 
1911 
1910 
191 1 
1912 



Thermocline. 



Thick- 
ness. 



Meters. 



FaU of 
tempera- 
ture. 



10.6 

11.5 

10.6 

9.4 

9.3 

6.8 

9.3 

9.6 

12.4 

8.5 

8.7 

10.2 

7.3 

7.8 

10.9 

9.7 

9.3 

12.3 

10.8 

8.1 



Per cent 

of total 

fall. 



74-7 
70. 6 
64.7 
61. 
58.5 
73-1 
73.2 

64. Q 

78. 5 
77-3 

60. 

70.4 
59-3 
49-4 
68.1 
36.1 

61. 2 

71-5 
75-5 
52. 6 



Fall per 
meter. 



Temper- 
ature at 
bottom. 



"C. 

11. 2 
8.2 
7-7 
9.8 
9. 2 
14. 6 
12.4 
9-7 
7-i 
13- S 
9.8 
9-3 
II. 9 
10. 2 
7-5 
9-3 
9.6 
8.2 

8.7 

12.4 



Hypolimnion. 



Thick- 



Meters. 

13.4 

63.5 

63.5 

110.6 

111.6 

6.0 

13.3 

40.8 

37.8 

8.1 

34.0 

34.0 

34.0 

168.4 

166.4 

72.5 

68.5 

54.0 

52.0 

57.0 



Fall of 
tempera- 
ture. 



3.2 
2.8 
3.4 
5.4 
5.2 
2.1 
3.1 
3.3 
2.3 
1.5 
3.8 
4.0 
3.6 
6.0 
3.5 
3.9 
5.1 
2.9 
2.5 
6.1 



Per cent 

of total 

fall. 



22.6 
17.2 
20.7 
35-1 
32.7 
22. 6 
34-4 

22. 3 

I4.5 

13-6 
36. 2 
27-5 
29-3 
38.0 

21. Q 

22. S 

33-5 
16. g 
17-5 
3Q. 6 



Fall per 
meter. 



°C. 
0.24 
.044 
.054 
.05 
.046 
.35 
.23 
.081 
.061 
.19 
.11 
.12 
.11 
.036 
.021 
.051 
.074 
.054 
.047 
.11 



Figures 5 and 6 give the temperature curves of the six major lakes to the depth of 
50 meters for the summers of 1910 and 191 1. All of them show the typical midsummer 
temperature curve of an inland lake. They show a striking resemblance to each other 
in form and there is less difference in the relative thickness of epilimnion and thermo- 
cline than might be expected. Keuka Lake departs in both years most widely from the 
others, and reasons can be assigned for this fact, but any of the other lakes might con- 
ceivably occupy any place in the set of curves. This close resemblance is an indication 
of the fact that the various lakes have absorbed nearly equal amounts of heat. The 
same fact is also indicated by the lower parts of the curve, which indicate in general 



A LIMNOLOGICAL STUDY OF THE FINGER LAKES. 



549 



warmer water for the shallower lakes. Keuka and Owasco Lakes, which hardly exceed 
50 meters in depth, are the warmest at the bottom in 1910. Skanea teles Lake accom- 
panies them in 191 1, but the observations were not at the best place. (See p. 540.) 
Seneca and Cayuga, the deepest of the lakes, are the coldest, and are both at about the 



OM 




Fig. 5. — Temperature curves of the six major Finger Lakes in 1910, shown to the depth of 50 meters. One vertical space represents 
5 meters in depth; one horizontal space represents 2° C See p. 548. 

same temperature. These facts of bottom temperatures should be expected on general 
principles, as stated by Wedderburn." But the resemblance of the upper part of the 
curves is greater than would be anticipated. 

" Wedderburn, E. M.: Temperatures of Scottish lochs. Bathymetrical survey of the fresh-water lochs of Scotland, vol. I, 
p. 97. Edinburgh, 1910. 



55o 



BULLETIN OF THE BUREAU OF FISHERIES. 



Surface and epUimnion. — The table shows that the surface temperatures of these lakes 
varied about as would be expected considering their size and depth. During the time 
necessary to visit the lakes no considerable depression of temperature occurred which 
would cool the surface, so that the observations in the different lakes are comparable. 



o/y 



/s 



Zo 



zs 



30 



3S 



40 



JS 



SO 



ZZ Off 




Fig. 6. — Temperature curves of the six major Finger Lakes in 191 1, shown to the depth of 50 meters. One vertical space represents 
S meters in depth ; one horizontal space represents 2 ° C See p. 548. 

During 1910 the weather was without a cold period until after the first week in September, 
and in 191 1 the first weeks of September were among the warmest of the season, and no 
marked depression of temperature occurred during August. There is therefore every 
reason to believe that the series represents the approximate maximum of the season, 
a maximum which would be surpassed during a succession of calm, hot days, but which 



A UMNOIyOGICAL STUDY OF THE FINGER LAKES. 55 1 

would not be exceeded in ordinary summer weather. The surface temperature of 
steep-sided lakes is necessarily lower than that of lakes with shallow margins, and 
that of the smaller lakes is, for similar reasons, usually higher than that of the larger. 

If we consider the six main lakes only, the mean thickness of the epilimnion in 1910 
was 1 1.5 meters (9 to 15 meters); in 191 1 it was 13.7 meters (11 to 16 meters). In 
twelve series of temperatures taken in six lakes in 1910 and 191 1, the mean thickness 
was 12.6 meters. No constant difference due to area or depth appears in the list. 
Keuka Lake had the thinnest epilimnion in both years, a condition undoubtedly due 
to the fact that it is narrower than any of the other lakes, and that its shores are on the 
whole higher and steeper than the others. The wind has therefore less opportunity 
to distribute the warm surface water. The effect of the same cause is found also in the 
fact that the annual gains of heat in Keuka Lake are the smallest of the six, as will be 
shown later, and also in its relatively low bottom temperature. Cayuga Lake indicates 
rather doubtfully a tendency toward an epilimnion a little thicker than the others. 
I believe this will be found to be the fact when a sufficient number of observations 
have been made. There is nothing conclusive, however, in the observations given, 
as they are quite within the range of accidental variation. 

I have added to the table of New York lakes the facts for Green Lake, Wisconsin, 
which lies in a climate not essentially different from that of central New York. These 
show that the epilimnion in these years had a thickness almost exactly the same as 
those of the New York lakes. Green Lake has a length of about 11.4 kilometers while 
those in New York vary from about 18 kilometers to more than 60 kilometers. Their 
mean breadth is of the same order of magnitude as that of Green Lake, and is therefore 
relatively less. This, however, makes little difference in the effect of wind in favor 
of Green Lake, since the long axis of Green Lake lies across the prevailing direction of 
the wind, or at least obliquely to it, while the New York lakes are much more nearly 
parallel to it. This fact, coupled with the greater length of the lakes, should make the 
influence of the wind as great for any of the lakes and much greater for some of them. 
In Seneca Lake, for instance, the currents induced by wind are often so strong that 
even when no wind is blowing a deep-sea thermometer will not sink perpendicularly 
unless extra weight is attached to the line. This condition never occurs in the Wisconsin 
lakes. 

It appears, therefore, that 12 to 15 meters is about the maximum thickness which 
can be expected in the epilimnion of an inland lake before the temperature of the water 
begins to decline. Such a statement applies only to lakes which lie under the topographic 
and climatic conditions of the lakes discussed. Variations are found and the thickness 
must be measured by meters and not by centimeters; but in any ordinary season the 
observer may confidently expect to find the thermocline about where he found it in 
previous years. It may be a little higher or lower, but the thickness of the epilimnion 
in the same lake will always be of the same order of magnitude. 

Thermocline. — We understand by the thermocline that thermal region of the lake 
lying immediately below the epilimnion, in which the temperature falls rapidly. This 



552 BULLETIN OF THE BUREAU OF FISHERIES. 

word was proposed by the senior author of this paper in 1897 as an equivalent for Richter's 
term " sprungschicht," and was so defined. " In this sense it has been included in the New 
Oxford Dictionary and also in the Century Dictionary. In 191 2 Wesenberg-Lund a 
redefined the word so as to restrict it to the meter of maximum fall of temperature, 
retaining the word "sprungschicht" for the larger stratum. We see no sufficient reason 
for this change, which would force a writer in English to invent a new equivalent for 
"sprungschicht" or else employ some long paraphrase for that term, such as Wedder- 
burn's "discontinuity layer." We therefore retain the term " thermocline " in its 
original sense, in which it has been adopted by English dictionaries. 

The terms "epilimnion," "thermocline," and " hypolimnion " are derived from 
that thermal condition of the lake which extends from early midsummer to the beginning 
of the homothermal period in autumn. Like all conditions that arise as a result of 
growth, this one comes on gradually, and its beginnings are not easy to define. In this 
paper the situation is treated and discussed as it appears in late summer during the 
equithermal period. Table 11 shows that the thermocline in the six major lakes (or 
seven with the addition of Green Lake, Wis.) was from 5 to 9 meters thick; that the 
fall of temperature in it was from 7.3 to 12. 3 ; and that this fall represented from 
about 40 per cent to nearly 80 per cent of the difference of temperature between the 
surface and the bottom of the lake. In the smaller lakes it is 4 to 6 meters thick, but 
contains a decline of temperature nearly as great as that of the larger lakes and one 
which represents a higher average percentage of the total fall. 

These figures have little significance in their details; since, as already stated, the 
thermocline is subject to constant alterations of thickness due to the oscillations of the 
water of the lakes. These changes may continually and rapidly alter the average rate 
of fall of temperature, and the total number of degrees included in the thermocline; the 
position of the meter of maximum descent of temperature, and the amount of fall 
included in it. The figures therefore represent in their range of variation about what 
might be expected in lakes of this size under average conditions of summer weather. 
Any of the major lakes might, under suitable conditions, show a thermocline like that 
of any one on the list. 

The general result, however, shows more than the single observation. The thermo- 
cline lies deeper in the larger lakes than in the smaller, and on the average is over 1.5 
meters thicker. This region represents the stratum in which the effects of the direct 
wind circulation die out, just as the epilimnion is the stratum in which a direct wind 
circulation is made possible by the cooling effect of night and of cool periods. It might 
be thought that in the larger lakes the greater influence of the winds would make the 
descent of temperature in the thermocline more gradual. This is true to a limited 
extent, as is best seen in the thermocline of Seneca Lake. It is more evident when large 
lakes are compared with very small ones. In general, however, the greater effect of 
wind in the larger lakes is rather to increase the thickness of the epilimnion than to 

o Bronsted, J. N., and Wesenburg-Lund, C: Chemisch-physikalische Untersuchungen der danischen Gewasser. Inter- 
nationale Revue der gesamten Hydrobiologie und Hydrographie, bd. iv, 1911, Biologisehes Supplement, sr. n, p. 262. Leipzig, 
1911-12. 



A LIMNOLOGICAE STUDY OF THE FINGER LAKES. 553 

modify the character of the thermocline. This means that as soon as the thermal 
resistance to mixture is strongly felt the work of the wind is rapidly cut off, more slowly 
in the larger lake, but not at all in proportion to its increased size. 

The last column in table m under the head of thermocline gives the temperature 
at the bottom of that region. It will be noted that these temperatures differ and show 
no relation to the temperature of the ground water. 

Hypolimnion. — In the hypolimnion the temperature falls at first rapidly; then 
more slowly, the curve approaching a straight line. The lower part of the very deep 
lakes may have a temperature nearly, or quite, the same through a considerable thickness 
of water. The division between thermocline and hypolimnion is not very definitely 
markedand is variable. The division of heat between these two regions is correspond- 
ingly uncertain. 

If similar climatic conditions are assumed, the temperature at the bottom of the 
lake varies with two factors, the size and the depth of the lake. On the size of the lake 
depends the efficiency of the wind until a certain area has been reached. This we have 
placed at the length of about 10 kilometers for lakes with a mean depth of 30 meters or 
more. Six of the Finger Lakes reach or exceed this area and depth, and therefore have 
the maximum bottom temperatures possible under the conditions of the season of obser- 
vation. Two of the lakes, Canadice and Otisco, are both too small and too shallow to 
permit the wind to have the maximum effect; and two others, Conesus and Hemlock, 
are too shallow. 

In the six larger lakes the bottom temperature in general follows the depth of the 
lakes, the shallower lakes having a higher temperature. In 1910 it varied from 7.0 in 
Owasco Take to 4.2 in Seneca Lake; and in 1911 from 5.3 to slightly above 4 in the 
same lakes. Owasco and Keuka Lakes have nearly the same maximum depth, but the 
bottom temperature of Keuka Lake is decidedly lower than that of Owasco in spite of 
its much greater length. This is due to the same cause that produced the thin epilimnion 
in Keuka Lake (p. 551). Skaneateles and Canandaigua Lakes, which have substantially 
the same length and depth, have also closely similar bottom temperatures, while the two 
larger and deeper lakes, Cayuga and Seneca, follow in the order of their depth. 

In 191 1 all of the bottom temperatures were lower than in 1910. The difference 
was almost the same in Owasco and Keuka Lakes (1.7 and i.6°, respectively), and the 
same is true for Skaneateles and Canandaigua Lakes (i.o° and 1 .i°, respectively). Cayuga 
Lake was about 0.3 lower in 191 1 and Seneca Lake was between o.i° and 0.2 lower. 
In 191 1 the temperature of Seneca Lake below 100 meters was very little above 4 . 
The mercury was slightly above the mark, but the reading would be less than 4.05 . 
Our deep-sea thermometer was not provided with an accessory thermometer for giving 
the temperature of the mercury at the time of reading and so making correction for the 
expansion of the mercury in the tube. It is therefore not improbable that the true 
temperature of the bottom water of Seneca Lake in 191 1 was slightly below 4.0 . 

The widely different temperatures of the hypolimnion in 1910 and 191 1 undoubtedly 
reflect the difference of the weather in the spring of those years, though there arc no 



554 BULLETIN OF THE BUREAU OF FISHERIES. 

direct observations to support the conclusion. In 1910 March and April were warm 
and May was unusually cold. The average of reports of the weather stations at Auburn, 
Geneva, Hemlock Lake, and Ithaca, all of them in the Finger Lake district, show that 
April, 1910, was 2.7 C. warmer and May 1.7 C. cooler than the average temperature 
for those months. In 191 1 these conditions were exactly reversed; March and April 
were somewhat, but not greatly, colder than the average, and May of that year was 
exceptionally warm. The average of the four stations named shows for April a deficiency 
of 0.4 C. and for May an excess of 4.1 C. This excess was more noteworthy since the 
first five days of the month were much colder than the average for that period. 

The high temperatures of the hypolimnion and the bottom water in 1910 and their 
lower condition in 191 1 were due to these differences in the weather. The exceptional 
heat of May, 191 1, caused the surface water to warm so rapidly that it prevented the 
distribution of heat to the deeper water, while the earlier part of the season was so cool 
that the lakes had warmed but little when the warmer weather began. In 19 10 the 
high temperatures of March and April came while the lakes were still below 4 , or close 
to that temperature, and the cool weather in May favored the distribution to deeper water 
of the heat acquired earlier or during that month. 

Owasco Lake in 191 2 had a bottom temperature slightly higher than in 19 10, and that 
of Skaneateles Lake was much above that of 1910 (see p. 565). No definite general 
features of the weather in spring can be assigned as the cause; and this is commonly 
the case, since bottom temperatures ordinarily depend on special events in the weather 
rather than on its general character. 

A word may be said regarding the temperature seiche as an agent for warming the 
hypolimnion. No observations have been made as yet which show that the temperature 
seiche has any noteworthy influence in this direction. The warming of the bottom 
water is effected chiefly in the early part of the season, before the thermocline is estab- 
lished, and while the differences in temperature between surface and bottom are slight. 
Under these conditions the direct effect of wind is great and that of the temperature 
seiche is nonexistent or feeble. When the epilimnion has been formed and the tempera- 
ture seiche can operate vigorously, the thermocline forms the zone of friction, or mixture, 
of the cooler and warmer water. Its mean descent is very slow, so far as observations 
have told the facts, after it gets far enough down to escape the ordinary direct influence 
of the wind, until it begins to sink again in consequence of the autumnal cooling of the 
lake. Thus it appears that but little work is done by the tenperature seiche in carrying 
the warm water downward, and this work, whether great or small, is mainly expended in 
extending the lower limits of the epilimnion and has little, if any, effect on the lower 
water. 

WINTER TEMPERATURES. 

Seneca and Cayuga Lakes are rarely frozen over except at the ends, and to a small 
extent along the shores. Local records show that Cayuga Lake was completely frozen 
in the following winters: 1796, 1816, 1818, 1836, 1856, 1875, 1884, 1904, 1912. The 

" The Auk, vol. 29, 191 2, p. 438. 



A UMNOLOGICAI, STUDY OF THE FINGER LAKES. 



555 



Seneca Lake has the following 



length of time that the ice remained is not stated, 
record : 

1855, closed February 24, opened March 15. 
1875, closed February 9-10, opened March 14. 
1885, closed February 24, opened March 6. 
1912, closed February u, opened March ro. 

Partially closed: 1856, 1865, 1904. Skimmed over with thin ice in spring: May 7, 1829, 
May 4, 1856, May 5, 1861, May 15, 1872, May 6, 1873, April 26, 1884.® We are not 
sure that this spring freezing extended over the entire expanse of the lake. 

The other lakes freeze regularly, though the central parts of deeper ones may 
remain open in mild winters. Freezing usually occurs in January or early February. 

Table in gives the important facts for the winter observations made on these lakes. 
The surface temperature of the lakes which were frozen is that of the water which rose 
in a hole cut through the ice. The temperatures of the frozen lakes are no doubt subject 
to less error than are those taken in the open water and more closely represent the mean 
temperature of the water of the lake. But the lakes were visited during a rather warm 
and calm period, so there is no reason to believe that any are seriously wrong. 

The temperature of Owasco Lake seems very low in 191 1, but table ix (p. 560) 
shows that the lake had lost the same amount of heat per unit of surface as Cayuga 
Lake. In the same table losses of heat in Seneca Lake seem to be low and those of 
Skaneateles Lake are high. Yet until we know the range of winter temperatures there 
is no reason to suspect serious error in either. In 191 1 Skaneateles Lake was only 
partly frozen and the process of cooling was still going on. In 1912 the lakes all froze 
over early on account of the unusually severe winter and this fact would lead us to 
expect rather high temperatures for the water of the lakes observed at that time. 

Table IV. — Winter Temperatures. 



Lakes. 


Year. 


Condition. 


Temper- 
ature, 
surface. 


Temper- 
ature, 
bottom. 




1911 

1911 




° C. 
2.00 

. 10 
.80 

3- 25 

.70 

1. 00 


°C. 

2-75 




Frozen 

...do 




2.2s 

3- SO 




1911 










1912 ; Frozen 


6 3- 10 






so meters. 


b TS 


meters. 







MEAN SUMMER TEMPERATURE. 



From a series of temperatures taken in the deepest water of the lake, the mean 
temperature of the water of the lake may be computed. If the mean temperature of 
each stratum is multiplied by the per cent of that stratum in the total volume of the 



« Data from Prof. E. H. Katon, Hobart College, Geneva, N. Y. 



46512°— 14- 



556 



BULLETIN OF THE BUREAU OF FISHERIES. 



lake and the several products are added, the result will show the mean temperature 
of the water. This is shown by the following example: 

Table V. — Method of Computing Mean Temperature of Lake: Canandaigua Lake, August 

20, 1910. 



Depth in 
meters. 


Temper- 
ature. 


Volume. 


Product. 






Per cent. 




0-10 


21.30 


o- 221 


4.707 


10-20 


14.50 


.184 


2 


668 


20-30 


7.40 


.165 


1 


221 


30-40 


6.25 


.147 




907 


40-so 


5-8s 


* 126 




737 


50-60 


5-75 


.094 




540 


60-70 


S-6 5 


.049 




277 


70-84 5.45 .014 
Mean temperature (Tm B ) = 




076 


11. 13 



These results are, of course, accurate in proportion as the temperatures recorded 
give a fair picture of the mean temperature of the several strata and in proportion as 
the hydrographic survey gives a correct account of the volume of the lake. Extreme 
accuracy can not be claimed in this case for either factor, but the results are approxi- 
mately correct. 

The question has been recently raised, whether a single series of temperatures can 
give a correct idea of the mean temperature of the water of the entire lake. In a 
recent review Halbf ass a states that the presence of the temperature seiche makes clear 
"die Bedeutungslosigkeit einer Beobachtungsserie in vertikaler Richtung in einem 
vereinzeltem Punkt eines Sees." This statement is entirely too strong, according to 
my observations, and, indeed, Halbfass in a later paper modifies the statement. No 
one in recent years would have believed that a single set of observations, or even 
numerous sets, made at one end of a lake would show the mean temperature of the 
water, least of all would such a series be trusted if taken during a windy period. This 
was true long before the temperature seiche was known. Our recent knowledge of the 
temperature seiche shows that conditions similar to those called out directly by wind 
may exist at almost any time on account of the oscillations following the influence of 
winds ; hence comes need for increased caution ; but it is by no means clear that a single 
series of temperatures taken under ordinary weather conditions, at or near the center 
of oscillation of a lake, are "without significance." No one would claim minute accu- 
racy for a result based on such a series; but there is as much reason as ever to believe 
that from such a series there can be derived a temperature for the water of the lake, 
which though not minutely exact, is approximately correct — close enough for all pur- 
poses of a general discussion. The result is of the right order of magnitude, as the 
following instances show. 

We can not find that many observers have taken series of temperatures with a 
view of testing the accuracy of results derived from a single series near the middle of 



o Halbfass, W.: Internationale Revue der gesamten Hydrobiologie und Hydrographie, vol. v, 1912, p. 471, Jan., 1913. 



A LIMNOLOGICAL STUDY OF THE FINGER LAKES. 



557 



the lake as compared with a mean temperature derived from numerous sets of observa- 
tions, but we have done much work with this end in view. In the New York lakes, 
series of three or four sets of observations were taken along the axes of three lakes. 
The results are shown in the following table. In each lake the stations are named from 
south to north; the mean temperature is computed to the depth of the water at the 
end stations; and the result from the center station is placed in italics. 

Table VI. — Mean Temperatures of Lakes as Computed from the Several Series of 
Observations, and from their Mean. 



Lakes. 


Year. 


A. 


B. 


c. 


T>. 


Mean. 




1910 
1911 
191 1 - 


"•94 
12. 17 

IS- 34 


12.00 
12.27 
15-13 


12. 50 
12. II 

14.80 






Do 


11.96 
14.82 













Explanation o? table-— The first series is computed to the depth of 50 meters; the second, to 40 meters: the third, to 30 
meters, this being the depth of the lake at the end stations. Figures in italics indicate the center station. 



Ju/y£7 


20 


29 


30 


31 


/tag / 


2 


3 


* | S 


_ 6 














• • 






1 

• * ** 


. 




-.1 


1 ' i ■• 

• 1... L.y-.- . ■ 


m 




*•• 


• 


• 


■ ■ 


• 


•• 


• 


•• 


. * 


I-" 








•••. 


•i 1 









w 



Fig. 7. — Mean temperature of Green Lake, Wis. From observations at center of lake in 1911. Computed to depth of 60 meters, 
the maximum depth at the center. All temperatures lie between 11°, or slightly below, and 12 . The position of the dots 
along the horizontal axis of the diagram indicates the day and hour of the observation. 

The above table shows that the mean temperature deduced from the center series 
differed by less than i per cent from that derived from three or four series. Similar 
results have been reached in more numerous cases in the Wisconsin lakes. In Lake 
Mendota in 1911, 1912, and 1913, observations were regularly taken at 10 to 12 different 
stations so placed as to give the distribution of heat in this lake, which is 9 kilometers 
long, 6 kilometers wide, and 24 meters deep. In series taken during these years at 
approximately regular intervals of time on 36 dates from June to September, the maxi- 
mum departure of the mean temperature derived from the 10 or 12 series from that 
derived from the single series at the center was less than 3 per cent and this was 
reached only once; and the mean departure was less than 1 per cent. The maximum 
differences were in June, when the lake was warming, and the distribution of heat was 
more irregular than later. In July, August, and September, the maximum departure 
was about 1.5 per cent and the mean 0.8 per cent. 

In five similar series taken in Green Lake, Wisconsin, the maximum departure of 
the mean temperature derived from the middle series and that derived from all was 
5 per cent and the mean was less than 2 per cent. 

From July 26 to August 5, 191 1, observations to determine the temperature seiche 
were made on Green Lake. During this work 83 series of temperatures were taken at 
the middle station. The results are shown in figure 7. 



558 



BULLETIN OF THE BUREAU OF FISHERIES. 



The diagram shows variations between the several observations; and also displays 
a slow but steady warming of the lake, as would be expected at that date. But for all 
purposes of a general discussion any one of these results might have been taken as 
representing the temperature of the lake quite as well as their mean, or as the mean of 
the several series of observations taken during this period at points along the whole 
length of the lake. 

This general result has been found to be true for observations taken at this time 
of year in all lakes during many years. It is therefore fair to conclude that the mean 
temperature of the water of a lake of simple form in late summer may be derived irom 
a single series of observations taken at or near the center of oscillation of the water. 

In the New York observations the least satisfactory series is that of Skaneateles 
Lake in 1911, when time did not permit me to go to the center of the lake. Seneca 
Lake offered the least favorable situation for taking the temperature in that the deepest 
water of this lake lies to the south of the center, about one-third of the distance from 
the south end. At so great a distance from the middle the water is subject to consid- 
erable oscillations. During 1910 five series of temperatures were taken from August 2 
to August 9. The mean temperature as deduced from the separate series ranged from 
7. 37 to 8.05 , with a mean of 7.71 ° — a variation of about 4.5 per cent on each side 
of the mean. This variation was wholly due to variations in the apparent distribution 
of the heat and not to actual changes of temperature in the lake, since the temperature 
of the 0-10 meter layer was practically constant at 19.5 to 19. 6°. The 10-20 meter 
stratum varied from 13. 2 to 16.3 — enough to give a difference of 0.28 in the mean 
temperature. The 20-30 meter stratum varied from 7.3 to 10.2 , which would give 
a variation of about 0.25 in the mean temperature. Thus the oscillations in the stratum 
between 10 meters and 30 meters account for about 80 per cent of the range of the tem- 
perature, and relatively little is due to changes above or below the depths named. This 
variation is considerably greater than would be expected in case of the other Jakes in 
which temperatures were taken at the center, or several series were taken along the 
axis of the lake. 

The following table shows the mean temperatures of the lakes as deduced from the 
observations taken, both for summer and winter. 

Table VII. — Mean Temperature op the Water of the New York Lakes, as Observed in 

Summer and in Winter. 



Lakes. 



Tm>, 

1910. 



Tm» ; 
191X. 



Tm», 
1911. 



Tm«, 
1912. 



Tm«, 
19 1 2. 



Canadice 

Canandaigua 

Cayuga 

Keuka 

Otisco 

O wasco 

Seneca 

Skaneateles 

Green (Wis.) 

<■ Oct. 18, and therefore below Tm 



19- 32 
11.07 

9. 26 
12. 17 
IS- 75 
13- 59 

7. 71 

10. 10 

11. 90 



0.83 
3-39 
I. 10 

2-13 



See p. 565. 



9.99 
8.94 
11.48 



12.86 

7-35 

10. 84 

11. 42 



2-39 
1.74 



13-93 



10. 21 
11.96 



A UMNOLOGICAL STUDY OF THE FINGER LAKES. 559 

Table vii shows that the mean temperature of the deeper lakes is lower in summer 
and higher in winter than that of the shallower, and that the difference between sum- 
mer and winter temperatures (or the annual range of temperature) is smaller in the 
case of the deeper lake. This must obviously be true if lakes are similar in other respects 
but differ in depth." The relation in these lakes between area, depth, and mean tem- 
perature is much more interesting than this simple statement indicates and will be 
described on a subsequent page. 

ANNUAL HEAT BUDGET. 

Forel was the first limnologist — first in this as in so many other matters — to deter- 
mine the amount of heat absorbed by a lake. He computed the number of calories 
necessary to raise a column of water of unit base in the deepest part of the lake to the 
temperature found in summer and he compared on this basis the amount of heat gained 
by different lakes. This method obviously permits accurate comparison only between 
lakes of similar area and depth. JHalbfass in 1905 improved the method in that he 
determined the mean temperature of the whole mass of the water of the lake. Knowing 
the volume of the water he was able to compute the total number of calories contained 
in the lake and also those gained or lost by the lake as it warmed or cooled. In an 
elaborate paper he gave the result of this method as applied to many European lakes. 6 
If this method is employed it is still necessary to select for comparison lakes of similar 
area and volume. 

In our judgment, if the heat budgets of lakes are to be compared at all, it is best 
to employ units of measurement of such a character that all lakes may be compared 
with each other, and such that this comparison may, if possible, reveal the relation of 
area and depth to the amount of the heat budget as well as the relation of geographical 
position and climate. Since all heat is taken in and given out by the surface of the 
water it seems best to us to express the amount of heat in the water and its variations 
in terms of calories per unit of that surface; and on the whole we have decided to 
employ the same units as those used by the meteorologist for measuring the energy 
received by the earth from the sun — the gram-calorie and the square centimeter. 

If the mean temperature of the water of a lake is known, it is easy to compute the 
amount of heat which was received by the lake in order to produce this temperature. 
If the mean temperature of the water is multiplied by the mean depth in centimeters, 
the result will be the number of gram -calories which the lake must receive on each square 
centimeter of its surface in order to raise the temperature of the water from o° C. to the 
temperature observed. The following table gives this result for the six major New York 
lakes and also for Green Lake, Wisconsin. 



"For a clear statement of this see Wedderburn, E. M., Temperatures of .Scottish lochs, in Bathymetrical survey of the 
fresh-water lochs of Scotland, vol. 1, p. 97, 1910. 

b Halbfass, W.: Ergebnisse ncuerer simultaner Temperaturemcssungcn in einigen ticferen Seen Europas. Petermanns 
Mitteilungen, 1910, bd. )i, p. 59. 



560 



BULLETIN OF THE BUREAU OF FISHERIES. 



Table VIII. — Calories per Square Centimeter of Surface Required to Raise Temperature 
of Water of Lake from Zero to Summer Temperature. 



Lakes. 



Dm. 


Tin' 


Calories 


Tm" 


meters. 


1910. 


1910. 


1911. 


38-8 


11.07 


43.000 


9.99 


54-5 


9. 26 


50, 000 


8-94 


30-5 


12.17 


37,000 


11.48 


29-3 


13-59 


40,000 


12.86 


88.6 


7.71 


68, 000 


7-35 


43-5 


10. 10 


44,000 


10.84 


33-1 


' 11.90 


39iOOo 


11.42 



Calories 
1911. 



Canandaigua 

Cayuga 

Keuka 

Owasco 

Seneca 

Skaneateles 

Green (Wisconsin) 



39,000 
49,000 
35>ooo 
38,000 
65,000 
47,000 
38.000 



It will be seen that the order of the lakes is substantially the same in each year 
and that the order is that of their depth, as was the case also with their mean tempera- 
tures. Keuka, Owasco, and Green Lakes, whose depths are nearly the same, are very 
close in the amount of heat which they have received. Keuka Lake is the lowest in 
both years, a result due, like the thinness of the epilimnion, to its sheltered position. 

This result represents what may be called the gross heat budget. It can be readily 
computed but it is of very little value since it does not represent any actual gains of 
heat. The winter temperature is never as low as zero, and other things being equal, it 
will be higher in the case of the deeper lake. The most important fact to be known is 
the annual heat budget of the lake — the amount of heat necessary to raise its water 
from the winter to the summer temperature — and to determine this we must know 
both the minimum and the maximum temperature of the water. In case of a lake whose 
surface freezes, the minimum temperature is that at the time of freezing, although in 
case of a large lake no great error would result from using any temperature taken during 
the ice period. In case of a lake that does not freeze, the date and value of the minimum 
temperature can be ascertained only by a study of the lake during the winter, but a 
series taken in February will not be far wrong. Such observations were made on four 
of these lakes in the winter of 1910-n and two in the winter of 1911-12, with the 
results shown in the following table. The minimum temperature derived from obser- 
vations taken in a single winter may be compared with the temperature both of the 
preceding and following summer; and thus two results can be obtained from three sets 
of observations. This method has been followed in the table. 

Table IX. — Difference Between Summer and Winter Temperatures of the Several Lakes. 

[Annual heat budgets stated in gram-calories per square centimeter of the surface of the lake.] 



Lakes. 


Dm 

meters. 


Tm» 
1910. 


Tm" 

1911. 


Tm" 
1911. 


Tm» 
1912. 


Tm" 
1912. 


Tm» 

1910 
minus 
Tm" 
1911. 


Calo- 
ries. 


Tm" 
1911 
minus 
Tm" 
1911. 


Calo- 
ries. 


Tm' 
1911 
minus 
Tm" 
1912. 


Calo- 
ries. 


Tm- 
1912 
minus 
Tm" 
1912. 


Calo- 
ries. 


Owasco 


54-5 
29-3 
88.6 
43-3 
33-1 


9. 26 
13- S9 

7.71 
10. 10 
11. 90 


2.23 
•83 
3-39 
1. 10 
2.13 


8.94 
12.86 

7-35 
10. 84 
11.42 






7-03 
ie. 76 
4-32 
9.00 
9-77 


38,200 
38,900 
38,300 
39, 200 
32, 200 


6.71 
12.03 
3-96 
9-74 
9.29 


36.500 
36, 600 
35.100 
42,400 
30, 600 










1.49 


13-93 


"•37 


34. 700 


12.44 


37.900 


Skaneateles 

Green (Wis.).. 


2-39 

1.74 


a IO. 21 

11.96 


8-45 
9.68 


36, 800 
31,900 


"7.82 
10. 22 


1 34, 000 
33.800 



" Taken Oct. 18, and therefore below Tm'. See p. 56s. 



A LIMNOEOGICAL STUDY OF THE FINGER LAKES. 561 

The table shows a surprising agreement of the heat budgets of the four lakes com- 
pared in 1910. The difference between the highest and the lowest result is only 1,000 
calories, or less than the heat which may be furnished to the surface of the lake on a 
bright summer's day. The agreement in 191 1 is nearly as ckse, with the exception of 
Skaneateles Lake, and the temperature of that lake was taken at some distance to the 
north of the center and may possibly be too high, though this result does not appear 
in the comparisons for 1912. (See also p. 565.) It would be expected that individual 
variations much greater than 1,000 calories would occur, since both the maximum and 
minimum temperatures must vary, and if in any individual case a high maximum and 
a low minimum came in the same season very considerable differences in the heat 
budget might be present. 

The table also shows that the heat budget of successive years is strikingly similar 
in the case of the same lake. This is especially noticeable in the case of Owasco Lake. 
It also appears that the heat budget is independent of the depths of the lakes, and also 
of their other dimensions within the limits of the lakes compared. 

The table seems, therefore, to warrant the following conclusions : 

1. The annual heat budget of the major New York lakes lies, in general, between 
35,000 and 40,000 gram-calories per square centimeter of surface. It may fall below 
the minimum or rise above the maximum stated, but in general the figures will fall 
between these numbers. 

2. For lakes of the form and size of these the heat budget is apparently independent 
of surface dimensions between the limits of 16 and 60 kilometers of length, and is inde- 
pendent of depth between the limits of 30 and 90 meters mean depth. It is probable 
that a lake much shallower than 30 meters would have a smaller heat budget, but a 
greater depth than 90 meters would produce no effect. 

3. Green Take, Wis., shows results constantly lower than the New York lakes. 
This is due rather to a high winter minimum than to a low summer maximum. It 
seems right, therefore, to place this lake in the same general class as the others and to 
state the following law: 

Inland lakes of the first class include those whose area and depth are such as to 
permit the maximum annual heat budget possible under the weather conditions of the 
season. Such a budget for lakes in the climatic and topographical conditions of the 
eastern United States ordinarily equals or exceeds 30,000 gram-calories per square 
centimeter of the lake's surface, and ordinarily lies between 30,000 and 40,000 gram- 
calories. Such lakes, under the conditions stated, will be 10 kilometers or more in 
length and will have a mean depth of 30 meters or more. 

This statement applies to lakes of simple outline whose length is five or more times 
their mean breadth. Lakes of irregular outline can not be compared with those of simple 
shape, and lakes whose proportions are essentially different from those given are not 
present in this region in sufficient numbers for study. 

4. It is obvious that for more accurate results a careful study of the temperatures 
of these lakes must be made, so that a mean temperature curve can be determined for 
each lake and compared with the temperature of the air and with the heat derived from 



562 BULLETIN OF THE BUREAU OP FISHERIES. 

the sun. Such a study will warrant far more definite conclusions and will probably 
modify details of the statement given above; but the work would consume several 
years and would require the combined efforts of many observers. 

WIND-DISTRIBUTED HEAT. 

The heat budgets of lakes can also be profitably compared in another way, which 
avoids the necessity of knowing the winter minimum temperature. 

The gains of heat in a lake of the temperate type may be divided in two parts, those 
below 4 and those above. So long as the temperature of the water is below 4 , the sur- 
face water becomes denser as it warms ; it tends to sink and thus carry the heat into the 
deeper water. The increase in density is small and the movement, if not aided by the 
wind, would be slow; but, under the meteorological conditions of early spring, gravity 
and wind together distribute the warm surface water very rapidly through the water of 
the lake. Thus there results a rapid and uniform warming of the water. During cold 
periods the lake loses heat; but since the surface water is only slightly warmer, if at all, 
than the lower strata, and since any cooling of the surface produces an inverse stratifica- 
tion, the losses which occur during such periods and during the night are ordinarily not 
great. Thus under usual conditions a lake moves rapidly and steadily up to the tem- 
perature of 4 during the spring. 

But after this point is .reached the situation wholly changes. Increase of tempera- 
ture in the water means decreased density. Gravity, so far from being an aid to dis- 
tribution, becomes an opponent; and the wind is left to do substantially the whole work 
not only without the aid of gravity, but against the resistance which gravity offers. 

This resistance is least at 4 and grows with increasing rapidity as the temperature 
rises above 4 . It follows that the action of the wind is most effective in early spring 
and becomes less efficient as the season advances and the lake warms. In April, and May 
also, the mean temperature of the air is above that of the surface of the lake, and losses 
of heat to the air are at a minimum. Thus in ordinary seasons by far the greater part of 
the heat which sun and sky furnish to the surface of the lake in April ma}' be stored in its 
water and is easily carried to considerable depths. The amount thus stored has never 
been measured for the New York lakes ; but for those of Wisconsin as much as 80 per cent 
or even more may thus be accumulated during April, and during May from 50 to 60 per 
cent of that which reaches the surface. 

As the season advances the mean temperature of the surface rises above that of the 
air. The thermal resistance of the water to mixture increases and the mean velocity of 
the wind declines. The gains of heat fall off correspondingly. Not more than 15 or 20 
per cent of the heat which falls on the surface of the lake is stored up in June, perhaps 
not more than 5 per cent in July, while in August the gains and losses of heat nearly 
balance. 

But during much of this period of decrease in storage, the quantity of heat delivered 
to the surface of the lake is increasing, that for July being ordinarily near the maximum 

o The general principles of this statement hold for all lakes. Numbers and dates will vary somewhat with the area and depth 
of the individual lake. 



A LIMNOLOGICAL, STUDY OF THE FINGER LAKES. 



563 



for the year and that for August not greatly below this. It follows that there is a great 
surplus of heat, potentia 1 ly available for warming the lake, which is lost to the lake 
because the means for distributing it are inefficient. 

If 40,000 gram-calories represents the maximum heat budget of such a lake, this 
is little more than half the amount of heat delivered by sun and sky between April 1 
and August 31. If 25,000 to 30,000 gram-calories represents a fair average for the wind- 
distributed heat, this again is less than half the heat delivered during that part of the 
warming period after the water of the lake has passed 4 . 

The following conclusions are therefore warranted: 

1. All lakes, whatever their area or depth, are on an approximate equality so far as 
their capacity for absorbing heat is concerned until their water has reached the tempera- 
ture of maximum density, or 4 , and this temperature is reached by all lakes early in the 
open season. 

2. The amount of heat absorbed after the temperature of 4 is passed, depends 
primarily on the efficiency with which the heat is carried from the surface to the deeper 
water, and this work is mainly effected by the wind. 

3. If we compare the gains of heat above 4 made by different lakes, we compare 
their wind-distributed heat, and so are able to compare the efficiency of their means of 
distribution. If the climatic and topographic conditions are similar, the efficiency of 
the means of distribution will increase with the dimensions and the depth of the lake up 
to a certain point. 

4. Since lakes reach the temperature of 4 early in the season, a comparison of their 
gains above 4 serves much the same purpose as a comparison of their annual heat budgets. 

To these statements there are several qualifications, none of which have been worked 
out quantitatively and only one of which need be stated. 

The amount of heat needed to raise the temperature of a lake from its winter con- 
dition to 4 may vary very greatly, especially in case of lakes that freeze. It is probable 
that more complete observations will show a greater proportionate range of variation in 
the amount to which lakes cool below the temperature of 4 than in the rise above 4 . 
The following table shows the facts for the lakes in question. 

Table X.— Calories per Square Centimeter of Surface Required to Raise Water of Lakes 
from Winter Temperature to 4 and from 4 to Summer Temperature. 



Lakes. 


Calories, 

Tm» to 4°, 

1911. 


Calories, 

4°toTm", 

1910. 


Calories, 

Tm w t0 4°, 

1912. 


Calories, 

4° to Tm ', 

ion. 


Cayuga 


9,600 
9,400 
5.400 
12,600 
6, 200 


28, 600 
28, 100 
32,900 
26,600 
26,000 


7,400 










29, 700 
29,300 
25.900 




7>ooo 
7.500 


Green 





It appears, therefore, that it may require as much as a month's .supply of heat, or 
even more, to raise the temperature of the lake from its winter condition to 4 . In 
such cases as that of Skaneateles Lake in 1910, it is possible that the lake may reach 



564 



BULLETIN OP THE BUREAU OF FISHERIES. 



4 so late that the whole season of later warming may be thrown over into the period 
when days are long and winds are light. Thus there might be a correspondingly small 
amount of wind-distributed heat. As a matter of fact, this result did not happen in 
the case cited, since Skaneateles Lake gained its full quota of heat in 191 1 and this will 
usually be the case. 

The last heat gained by a lake is in the epilimnion and therefore is near the surface — 
in the New York lakes not below 15 meters. The wind velocity from mid- July on through 
August is not essentially less than it is during the preceding six weeks. The surface is 
still receiving a great amount of heat, and the increasing length of the night adds to the 
chances of distribution. Thus in general a lake gains by the middle of August all of the 
heat that the wind can get into its depths; and whether a lake starts to accumulate its 
wind-distributed heat two weeks or so earlier or later makes little if any difference in 
the general result. In any case the heat is supplied to the deeper water of the lake early 
in the season before the velocity of the wind has greatly fallen. 

Table XI. — Calories per Square Centimeter of Surface Needed to Raise Water of Lakes 
from 4 to Summer Temperature, or the Amount of Wind-Distributed Heat. 



Lakes. 


Dm. 
meters. 


Tm«-4, 

1910. 


Calories. 


Tm»-4, 
1911. 


Calories. 


Tm"-4, 
1912. 


Calories. 




38.8 

54- S 
30-S 
29-3 
88.6 

43-5 
33-1 


7.07 
5-26 
8.17 
9-59 
3-71 
6.10 
7.90 


27,400 
28,600 
24,900 
28, 100 
32,900 
26, 700 
23,90° 


5-99 
4-94 

7.48 
8.86 
3-35 
6.84 

7.42 


23,200 
26,900 
22,800 
26,000 
29, 700 
29,700 
23,500 




















9-93 


29, 000 








'(«') 


Green (Wis.) 


7.96 







" See p. 565. 

Table xi shows that Keuka Lake has the smallest amount of wind-distributed 
heat in both years and Seneca Lake the largest. So far as the former lake is concerned, 
it seems probable that this will be the regular condition, the narrowness of the lake 
and its steeper banks reducing the influence of the wind. It is not so certain that the 
result in Seneca Lake will be confirmed by further study, although this conclusion 
seems probable. No two lakes can be more nearly equal in area or similar in topo- 
graphical condition than are Seneca and Cayuga Lakes. But three factors contribute 
to give Seneca an advantage in gaining heat during the early part of the season — 
steeper slopes, greater depth, and greater volume. The result of these was that Seneca 
Lake absorbed more heat into its deeper water than did Cayuga in 19 10. The water 
of Seneca Lake below 30 meters received 1,600 calories per square centimeter of the sur- 
face of the lake more than the corresponding water of Cayuga, and in 191 1 the excess 
was about 300 calories. 

The steeper sides of Seneca Lake give it an advantage in distributing heat to the 
deeper water, since the large shoal areas at the north end of Cayuga Lake tend to keep 
the return currents near the surface; but the chief advantage of Seneca Lake is in the 
greater reduced thickness (p. 566) of its several strata. If the results for Cayuga and 



A LIMNOIyOGICAI, STUDY OF THE FINGER LAKES. 565 

Seneca Lakes are compared in table xn, it will be seen that the water of Cayuga Lake 
has a higher temperature than the corresponding stratum of Seneca Lake, but the strata 
of Seneca have the greater reduced thickness and so contain more heat. 

But for the present the most important conclusion from the table lies in the general 
fact that for lakes 10 kilometers or more in length and 30 meters or more in mean 
depth, the annual gains of wind-distributed heat are on the whole independent of area 
or depth and range from something below 25,000 calories to something above 30,000 
calories. It is not asserted that in these lakes different areas and depths have no 
effect. The contrary is true, as is shown above, but in general these effects lie within 
the range of the variation due to local conditions in wind and weather. No doubt 
under exactly similar conditions the largest and deepest lake will gain most heat, but 
the effects of area and depth are such that they may be overcome by variations of 
weather. In 1910, for instance, Owasco Lake, the smallest and shallowest of the New 
York group, stands third in the amount of heat, and in 191 1 Skaneateles Lake is equal 
to Seneca Lake and is much above the far larger and deeper Cayuga Lake. 

From these facts we may give a second definition for inland lakes of the first class : 
In inland lakes of the first class the wind-distributed heat, Dm(Tm s — 4), is about 25,000 
gram-calories per square centimeter of surface and usually exceeds that sum. Such 
lakes will be, under the climatic conditions of the eastern United States, 10 kilometers 
or more long and will have a mean depth of 30 meters or more. If such a lake falls 
below 25,000 calories, the deficiency will be due to exceptional conditions of topography 
or weather. If its gains rise above 30,000 calories, this result will also be exceptional. 
Further study is needed to make these statements more accurate in detail. Such 
study will show the presence and limits of the influence of area and depth within this 
class of lakes. 

In 1 91 2 temperatures were read in Skaneateles Lake on October 18, too late for 
the maximum temperature of the upper water. The water at the bottom was 6.3 , 
much higher than in 1910 or 1911. The temperatures below the depth of 40 meters 
would be practically unaltered on October 18. If these are taken as they were found, 
and if we assume that the temperature of the water above 40 meters was the same in 
1912 as in 1910, then Tm s for 1912 would be 10.72 . If we, in like manner, assume 
for 1 91 2 the same temperature for the upper water as in 191 1, then Tm s 191 2 would 
be 1 1. 33 . On the basis of the latter figures the maximum annual heat budget between 
Tm w 1911 (1.10 ) and Tm 8 1912 (11. 33 ) would be 44,500 gram-calories. This shows 
that under favorable conditions the annual heat budget of these lakes may go as high 
as 45,000 gram-calories per square centimeter. The wind-distributed heat in 191 2 
for Skaneateles Lake on these assumptions would be 29,200 gram-calories and 31,800 
gram-calories, respectively. 

DISTRIBUTION OF HEAT. 

Distribution to thermal regions (fig. 8). — -The formula for the amount of wind- 
distributed heat is Dm(Tm 8 -4). The product is the number of gram-calories per 
square centimeter of surface which the lake must receive that its temperature may 



5 66 



BULLETIN OF THE BUREAU OF FISHERIES. 



rise from 4 to its summer temperature. In what proportion is this heat so received 
distributed to the three main thermal regions? 

In order to answer this question the mean temperature of each region must be 
known, and to determine this the reduced thickness of each region must be ascertained. 



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Fig. 8.— Distribution of wind-distributed heat in 1910, in Canadice (Cn), Owasco (O), Cayuga (Cy), and Seneca (S) Lakes. 
Depth in meters; heat in gram-calories per square centimeter of surface of the lakes. Diagram extends to 100 meters. The 
curves of Seneca and Cayuga Lakes, from 50 meters to 100 meters, are repeated on a more open scale. (See p. 572.) 

In table xii the column marked "Extent" shows the thickness of each thermal region 
as measured in meters below the surface of the lake; the column marked "R. T." 
(reduced thickness), shows its thickness as referred to the area of the surface of the lake. 



A LIMNOLOGICAL STUDY OF THE FINGER LAKES. 



567 



It is ascertained, like the mean depth of the lake, by dividing the volume of the water 
of the region by the area of the surface. The reduced thickness of the region thus 
differs from its mean thickness in that the reduced thickness of the region is in all cases 
referred to the area of the surface of the lake, while the mean thickness of a given stratum 
would be its thickness referred (ordinarily) to its own upper boundary plane. Table 
xii shows the distribution of the calories received by a unit of the surface of the six 
major lakes to their thermal regions. 

Table XII. — Showing Extent and Reduced Thickness op the Three Thermal Regions in the 
Six Major Lakes, Their Temperature, and the Number of Calories per Square Centi- 
meter op Surface of the Lake Distributed to Each Region. 

[The sums of the calories in each lake may differ slightly from those given in the general table, owing to the different method 

of computation.] 



Region. 


Ex- 
tent. 


R.T. 


Tm-4. 


Calo- 
ries. 


Per 

cent. 


Region. 


Ex- 
tent. 


R.T. 


Tm-4. 


Calo- 
ries. 


Per 

cent. 


CANANDAIGUA LAKE, 

1910. 


Meters. 
0-12 
12-20 
20-84 


Meters. 

10. 

5-6 

23-1 


16.8 
9-3 
2.73 


16, 800 
5,200 
5,200 


61.9 

19. 1 
19. 


Owasco Lake, 1910. 

Epilimninn 


Meters. 
0—12 
12-20 
20-54 


Meters. 
10. 6 
5-6 
13-1 


16.3 
9.9 

4.0 


17,300 
5,600 
5,200 


61.6 






19.7 

18.7 








Owasco Lake, 1911. 

EpilimTiinn 






29- 3 


9-59 


28, 100 








38.7 


7.07 


27,200 








0-12 
12-20 
20-54 


10.6 
5-6 
13- 1 


15-9 
10. 6 

2.41 


16,800 
6,000 
3,200 




CANANDAIGUA LAKE, 


0-12 

12-20 
20-84 


10. 
S-6 
23-1 


IS- 5 
9.2 
1.04 


15,500 
5,200 
2,400 


66.4 
22. 
11. 6 


64-5 
22.8 










12. 7 




Seneca Lake, 1910. 






29-3 


8.86 


26,000 












38.7 


S-99 


23,200 




0-12 

12-20 
20-188 


II- 5 
6.2 
70.9 


15-4 

10. 2 

1. 21 


17,700 
6,400 
8,800 






0-15 

15-22 

22-133 


11. 8 
4-62 
38.3 


15-5 

10.3 

I. 41 


18, 300 
4,800 
5,400 


64. 2 
16. 9 
18.9 


53-8 
19- S 
21. 7 




Thermoclrae 








Seneca Lake, 1911. 






88.6 


3-71 


32,900 












54-7 


S-26 


28,500 




0-15 

15-22 

22-188 


13-8 

6.0 

68.8 


15-4 
8.6 
0-47 


21,200 
5,200 
3,300 




Cayuga Lake, 191 1. 


0-16 

16-21 

21-133 


12.5 

3-3 

38.7 


15-2 
9-2 

1. 14 


19,000 
3,300 
4.400 


71. 1 
12.4 
16.5 


71-5 
17-5 












Skaneateles Lake, 
1910. 








88.6 


3-35 


29, 700 












54-7 


4.94 


26, 700 




0-9 
9-18 

18-90 


8.0 
6-5 
29.0 


15-7 
10. 1 
2.97 


12, 500 
6, 600 
7,600 




Keuka Lake, 1910. 


0-9 
9-15 
15-5° 


8.4 
4.9 

17. 2 


16.8 
9.2 

3-45 


14, 100 
4,500 
6,300 


56.6 
18. 1 

25-3 


46.9 
24.7 
28.4 












Skaneatei.es Lake, 
1911. 






43-5 


6. 10 


26, 700 








30.5 


8.17 


24,900 








0-16 
16-22 
22. 90 


13- 
4. 2 
26.3 


J5-5 
10.4 
1.82 


20, 200 
4,300 
4,700 




Kjsuka Lake, 191 1. 
Epilimnion 


o-n 
11-18 
18-56 


10. 

5-4 
15- 1 


16.2 
7-8 
1.68 


16, 200 
4,100 
2,500 


71.0 
18.0 
11. 


67.8 
14.4 
17.8 


Thcrmocline 






Hypolimnion 








30- 5 


7-48 


22,800 






43-5 


6.74 


29, 200 






568 BULLETIN OF THE BUREAU OF FISHERIES. 

Inspection of table xn shows that the mean temperature of the epilimnion and 
the thermocline are not very variable in the six major lakes. In the first region Tm s -4 
equals 15. 66°, as the mean of 12 observations, ranging from 15. 2 to 16. 8°. For the 
thermocline the mean is 9.56 , ranging from 7. 8° to 10.6 . The differences in the 
amount of heat stored by a lake in these regions are due much more to the thickness of 
the stratum than to its temperature. For instance, in Seneca Lake in 1910 the tem- 
perature of the thermocline was 19.4 , and in Skaneateles Lake in 1910 it was 19.7 . 
But its thickness in Seneca Lake was 15 meters, and only 9 meters in Skaneateles; and 
the wind-distributed heat in the epilimnion of the former lake was therefore over 75 per 
cent greater than that of the latter. 

It appears from the table that a very large part of the wind-distributed heat is in 
the epilimnion. The upper 10 or 15 meters of a lake, even 60 kilometers long and nearly 
200 meters deep, contain 50 to 70 per cent of the heat, or even more. If to this stratum 
is added that which lies immediately below it and has derived its heat from it, it appears 
that the upper 20 meters contain 70 to 80 per cent, or even 90 per cent, of the wind- 
distributed heat. (See table xin.) This limitation of the heat to the upper strata is 
responsible not only for the sharply-defined thermocline, but also for the general 
uniformity in the amount of wind-distributed heat in the heat budget of the several 
lakes. A large percentage of the heat is always near the surface in summer. During 
the period of light winds and summer weather, when heat is furnished far in excess of 
the capacity of the distributing agents, so much is lost in any case that there is enough 
for any lake to get the maximum possible supply, and any deficiency is likely to be due 
to the distributing agents, and not to lack of supply. Still more, any loss caused 
by a short cool period during the summer may be quickly repaired, since no violent 
wind is needed to distribute the heat to water near the surface. Indeed, such a cool 
period may well be the indirect cause of the gain of heat. It allows the heat already in 
the lake to be distributed to a greater depth, while the surface will rapidly renew its 
supply during the succeeding warm days. 

The heat distributed to the hypolimnion is extremely variable both in quantity 
and in the per cent it constitutes of the total heat. If the sums of the calories found 
in the epilimnion and thermocline are compared for the 12 observations, it will be 
found that the mean is 22,200. The mean departure of each observation from the 
mean is about 8 per cent; the maximum departures are +19 per cent and — 16 per cent; 
and the range is about 35 per cent of the mean. In the case of the hypolimnion the 
mean amount of heat is 4,900 calories. The mean departure of each observation is 
28 per cent of this sum, the maximum is +80 per cent and —50 per cent, with a range 
of 130 per cent of the mean. Not only so, but the difference in the same lake in suc- 
cessive years is even more striking. The hypolimnion of Seneca Lake received 8,800 
calories per square centimeter of surface in 1910, and only 3,250 calories in 191 1. Keuka 
Lake had 6,300 calories in 1910 and 2,700 calories in 191 1. The mean of the six lakes 
for 191 1 was hardly more than half as great as that for 1910 (6,400 and 3,400 calories), 
and the largest amount in 191 1 (4,800 calories in Skaneateles Lake) was below the 



A LIMNOLOGICAL STUDY OF THE FINGER LAKES. 569 

smallest of the former year (5,000 calories in Cayuga Lake). This distribution illus- 
trates several principles. 

1. The amount of heat received by the hypolimnion depended on the vicissitudes 
of weather during the early part of the warming period. (See p. 553.) 

2. The lakes of the district were all similarly affected in each year. 

3. In spite of this general similarity there are great individual differences, and 
neither the size nor the depth of the lake seem to be decisive in influencing the amount 
of heat given to the hypolimnion. In 1910 Skaneateles Lake,- with a hypolimnion 
72 meters in maximum thickness and 29 meters in mean thickness, received 7,600 
calories. Seneca Lake, with a hypolimnion 168 meters in maximum thickness and 
71 meters in mean thickness, received only 8,800 calories. This was true in spite of 
the fact that Seneca Lake is far larger and its hypolimnion began only 2 meters farther 
from the surface. In 191 1 Seneca Lake received less heat in its hypolimnion than 
Skaneateles Lake (3,250 calories and 4,800 calories, respectively); less than Cayuga 
Lake (4,400 calories); and practically the same as Owasco Lake (3,150 calories), the 
smallest and shallowest of the lakes. 

Distribution to the several 10-meter strata. — It will be of interest to consider the 
distribution of heat by the wind to different depths below the surface, as well as its 
distribution to the different thermal regions. This distribution may be expressed in 
two ways: 

1. The heat absorbed by each square centimeter of the surface may be followed 
through the lake and the amount determined which is absorbed by or passed through 
each successive stratum, and the result may be expressed in calories per square centi- 
meter of the surface of the lake. 

2. The boundary planes of the successive strata of the lake become smaller in 
proportion to their distance from the surface. It is possible, therefore, to state not 
merely the number of calories per square centimeter of the lake's surface which pass 
through any given plane, but also the number of calories which pass through each 
centimeter of the plane itself. 

An example will make this clear. The water of Cayuga Lake absorbed 28,600 
gram-calories through each square centimeter of the surface in 1910; 12,800 calories 
were left in the 0-10 meter stratum. Thus there remained at 10 meters 15,800 calories 
of those received by each square centimeter of the surface, and this amount was dis- 
tributed to the water below the depth of 10 meters. But the area of the lake at 10 
meters is 72.5 per cent of the surface area, and the number of calories which passed 
through each square centimeter of this plane is correspondingly greater. Through each 

square centimeter of the 10-meter plane there passed 21,800 calories, or — . 



57o 



BULLETIN OF THE BUREAU OF FISHERIES. 



Table XIII. — Distribution of Heat to the Several io-Meter or s-Meter Strata. 

[In the tables the upper figures of columns 2 and 4 show the number of calories per square centimeter of surface of the lake 
necessary to raise the temperature of the water from 4° to the summer temperature in 1910 and 1911, and the remaining figures 
show the number of such calories remaining at the several depths. Columns 6 and 7 show the number of calories present at each 
depth per square centimeter of the area at that depth. They are derived from the numbers of columns 2 and 4 by dividing them 
by the per cent of area given in column 3, tables xv-xvn. Columns 10 and 12 show the number of calories per square centimeter 
of surface left between the depths specified. They are computed in the same way as the data in table xn. The data for Otisco 
and Canadice Lakes refer only to 1910.] 

CANANDAIGUA LAKE. 



Depth, 
meters. 


Calories per square centimeter of sur- 
face remaining at depth named. 


Calories per square 
centimeter of area 
at depth named. 


Depth, 
meters. 


R. T.. 

meters. 


Calories per square centimeter 
of surface left between depths 
named. 


1910 


Per 
cent. 


1911 


Per 
cent. 


1910 


1911 


1910 


Per 

cent. 


191 1 


Per 

cent. 



10 
20 
3° 
40 
5° 
60 
70 
84 


27,400 

12,800 

5,400 

3,200 

1,900 

1,000 

380 

80 


100- 

46.7 
19.7 
11. 7 

6.Q 

3.6 

1.4 

■3 


23,200 

9,700 

2,400 

1,100 

550 

260 

85 

15 


100. 

41.8 

10.4 

4-7 
2.4 
1. 1 

■4 
.06 


27, 400 
16,900 
8,000 
5,300 
3,500 
2,300 
1,300 
760 


23,200 

12, 800 

3,500 

1,800 

1,000 

600 

290 

140 


O-IO 

10-20 
20-30 
30-40 
40-50 
50-60 
60-70 
70-84 


8.56 
7. 16 
6-43 
5-7i 
4.88 
3-65 
1. 90 
■53 


14,600 

7,400 

2,200 

1,300 

900 

620 

300 

80 


53-3 
27.0 
8.0 
4-7 
3-3 

2-3 

1. 1 
■3 


13,500 

7,300 

1,300 

550 

290 

175 

70 

IS 


58.2 

31-5 

5-6 

2.4 

1. 2 

.8 

■3 



























CAYUGA LAKE. 






28, 600 


100. 


26, 900 


100.0 


28, 600 


26,900 


0- IO 


8.34 


12, 800 


44-8 


13,400 


49 .8 


IO 


15,800 


55-2 


13, 500 


SO. 2 


21,800 


18, 600 


10- 20 


6.88 


9,400 


32-9 


9,000 


33-5 


20 


6,400 


22-4 


4,500 


16.7 


9,800 


6,900 


20- 30 


6.28 


3,000 


10. 5 


2,600 


9-7 


30 


3,400 


II. Q 


1,900 


7-i 


5,600 


3,100 


30- 40 


5-75 


1,400 


4-0 


900 


3-4 


40 


2,000 


7.0 


1,000 


3-7 


3,700 


1,800 


40- 50 


5. 11 


700 


2.4 


350 


1-3 


50 


1,300 


4-6 


650 


2.4 


2,700 


1,400 


50- 60 


4-52 


400 


1.4 


180 


■ 7 


60 


900 


3-2 


470 


1.8 


2,100 


1,100 


60- 70 


4.05 


250 


■9 


140 


■5 


70 


650 


2.3 


330 


1. 2 


1,700 


860 


70- 80 


3- 62 


190 


.6 


130 


■ S 


80 


460 


1.6 


200 


■ 7 


1,300 


590 


80-100 


5-88 


290 


1. 


120 


•4 


100 


170 


.6 


80 


■3 


690 


320 


100-133 


4.21 


170 


.6 


80 


■3 


133 



















































KEUKA LAKE. 






24, 900 


too. 


22,800 


100. 


24, 900 


22,800 


O-IO 


9. 21 


15,000 


60.2 


15, 000 


65.8 


IO 


9,900 


39-8 


7,800 


34-2 


11,800 


9,200 


10-20 


7.84 


5,300 


21.3 


5,700 


25-0 


20 


4,600 


18.5 


2,100 


9.2 


6,300 


2,900 


20-30 


6.44 


2,500 


II. I 


1,300 


5-7 


30 


2,100 


7-4 


800 


3-5 


3,800 


1,400 


30-40 


4-39 


1,400 


4.6 


570 


2-5 


40 


690 


2.8 


230 


I. 


2,100 


720 


40-50 


2. 26 


600 


2.4 


200 


■9 


50 

56 


90 


■4 


30 


. 1 


600 


200 


50-56 


•37 


90 


■4 


30 


. 1 



























OWASCO LAKE. 






28, 100 


IOO- 


26, 000 


IOO. 


28, 100 


26,000 


O-IO 


8.94 


14,750 


52-7 


14,300 


55-4 


IO 


13, 300 


47-3 


11,600 


44.6 


16,700 


14, 600 


10-20 


7.18 


8,000 


27. 1 


8,200 


34-3 


20 


5,400 


19. 2 


3,400 


10.3 


8,400 


5,300 


20-30 


5-95 


2,800 


9-9 


2,200 


5-7 


30 


2,600 


9-3 


1,200 


4.6 


4,700 


2,200 


30-40 


4. 60 


1,700 


6.2 


830 


3-2 


40 

54 


860 


3-1 


370 


1-4 


2,200 


960 


40-54 


2. 62 


850 


31 


370 


1.4 



























A EIMNOEOGICAL- STUDY OP THE FINGER LAKES. 



57i 



Table XIII. — Distribution of Heat to the Several io-Meter or 5-Meter Strata — Continued. 

SENECA lake. 



Depth, 


Calories per square centimeter of sur- 
face remaining at depth named. 


Calories per square 
centimeter of area 
at depth named. 


Depth, 
meters. 


R. T., 

meters. 


Calories per square centimeter 
of surface left between depths 
named. 


meters. 


























Per 




Per 












Per 




Per 




1910 


cent. 


19II 


cent. 


1910 










cent. 




cent. 


o 


32,900 


100. 


29, 600 


100. 


32,900 


29,600 


O-IO 


9-35 


14,600 


44.4 


14,600 


40-5 


IO 


18,300 


55-6 


15,000 


50-5 


21,000 


17,200 


10-20 


8.40 


9,600 


20- 2 


10, 200 


34-3 


20 


8,700 


26.4 


4,800 


16.2 


10, 800 


6,000 


20-30 


7.86 


3,700 


II. 2 


2,600 


8.8 


3° 


5,000 


15-2 


2,200 


7-4 


6,600 


2,900 


30-40 


7.41 


1,800 


5-5 


800 


2.7 


40 


3,200 


9-7 


1,400 


4-7 


4,500 


2,000 


40-50 


6. 92 


1,000 


3.0 


400 


1-3 


5° 


2,200 


6.7 


1,000 


3-4 


3,300 


1,500 


50-60 


6.49 


600 


1.8 


280 


1.0 


60 


1,600 


4-9 


720 


2.4 


2,600 


1,200 


60-70 


S-89 


450 


1.4 


160 


.6 


70 


1,150 


3-5 


540 


1.8 


2,000 


950 


70-80 


5-52 


320 


1.0 


160 


.6 


80 


830 


2-5 


380 


1-3 


800 


700 


80-100 


9.82 


460 


1.4 


200 


■ 7 


100 


370 


I.I 


180 


■7 


800 


400 


100-150 


20. 2 


305 


■9 


178 


■7 


150 


65 


.2 


2 




290 


10 


150-188 


3-3 


65 


. 2 


2 




188 



















































skaneateles lake. 






26, 700 


IOO. 


29, 700 


100.0 


26, 700 


29, 700 


0-10 


8-75 


13, 700 


SI- 3 


13,600 


45-8 


IO 


13,000 


48-7 


16, 100 


54-2 


17, 000 


21,300 


10-20 


7.14 


6,400 


24.0 


9,900 


33-3 


20 


6,600 


24.7 


6,200 


20. Q 


9,800 


9,200 


20-30 


6-39 


2,300 


18.6 


3,100 


10.4 


30 


4,300 


16. 1 


3,100 


10.5 


7,100 


5,100 


30-40 


5- 75 


1,500 


5-6 


1,200 


4-1 


40 


2,800 


10.5 


1,900 


6.4 


5,200 


3,400 


40-50 


5.06 


1,100 


4.1 


900 


3-0 


So 


1,700 


6.4 


1,000 


3-4 


3,700 


2,200 


50-60 


4.28 


730 


2.8 


510 


1.8 


60 


970 


3-6 


490 


1.6 


2,500 


1,300 


60-70 


3-37 


560 


2. 1 


340 


1. 1 


70 


410 


i-5 


150 


•5 


1,400 


520 


70-80 


2.13 


330 


I. 2 


110 


■4 


80 
90 


80 


■3 


40 


. 1 


550 


220 


80-90 


•56 


80 


■3 


40 


. I 



























CANADICE LAKE, 1910. 





5 

IO 

15 
20 
25 


19, 400 
11,200 
4,700 
2,000 
700 


100.0 
57-7 
24.2 
10.3 
3-6 






19, 400 

13,400 

6,200 

3,200 

1,300 




0-5 
5-10 
10-15 
15-20 
20-25 


4-54 
4. 00 
3-48 
2.79 
1-59 


8,200 
6,500 
2,700 
1,300 
700 


42-3 

33-5 

13-9 

6.7 

3-6 








* 









































































OTISCO LAKE, 1910. 





5 

IO 

IS 
20 


17, 000 

9,100 

3,700 

800 


100.0 

53-5 

21.8 

4-7 






17,000 
13,000 
6,200 
1,550 




0-5 
5-1° 
10-15 
15-20 


4.22 
3-25 
2-79 

•94 


7,900 

5,400 

2,900 

800 


46-5 

31.8 

17. 1 

4-7 







































































The above table shows the amount and per cent of the total heat absorbed by the 
surface which is left in each 10-meter stratum of the lakes studied. The rapidity 
with which the heat declines is evident, and shows how hard the wind finds the task of 
overcoming the thermal resistance. A single illustration shows this in a striking manner. 
We may allow 1,000 calories per square centimeter as a full (not a mean) supply to 
the surface for a single summer day. We find in the various major lakes that this 
amount was distributed in 1910 to the water below a depth of 35 to 60 meters, and below 
30 to 50 meters in 191 1. Thus the work of the entire season was necessary to carry to 
46512°— 14 4 



572 BULLETIN OF THE BUREAU OF FISHERIES. 

a depth greater than the number stated an amount of heat equal to one maximum 
day's supply in summer. 

Nor is this all. The upper 10 meters contain from 45 to 65 per cent or more of the 
heat absorbed. This region is that in which nocturnal cooling, the action of waves, and 
the direct penetration of the sun aid in distributing the heat. At depths where these 
agencies cease to act the influence of the wind declines very rapidly. 

It is worth while to call attention to the fact that the distribution of heat is strikingly 
similar in each year and that the two years show marked differences. 

Figure 8 (p. 566) shows in graphic form the results for 1910 in the case of Owasco 
Lake and Seneca and Cayuga Lakes, respectively the largest and deepest and the smallest 
and shallowest of the lakes. The greater quantity of heat in Seneca Lake was due 
almost wholly to the greater amount distributed to the hypolimnion, that in the epilim- 
nion and thermocline being about equal in both lakes. It thus appears that in general 
the distribution of heat is independent of the area or depth of the lakes, in the case of 
lakes of the first class. The mean of observations made in Green Lake, Wisconsin, 
during 10 or 12 years falls midway between the results for Cayuga Lake in 19 10 and 
191 1, and shows that this lake also belongs to lakes of the first class. The curve of 
heat distribution for Canadice Lake is added to show the facts for a smaller lake. 

HEAT SUPPLY OF THE SMALLER LAKES. 

We must now consider the heat supply of the two smaller lakes, of which we have 
hydrographic surveys, Canadice and Otisco. We are unable to discuss their annual 
heat budget, as no winter observations have been made on them, but the amount of 
wind-distributed heat can easily be ascertained. It will be remembered that Otisco 
Lake has an available length of about 7.33 kilometers and a mean breadth of 0.93 kilo- 
meters; its maximum depth is 20.1 meters, and its mean depth 11.2 meters. The 
corresponding figures for Canadice Lake are: Length, 5.12 kilometers; mean breadth, 
0.51 kilometers; maximum depth, 25.4 meters; mean depth, 16.4 meters. The ratio 

— —is about o. S3 in Otisco, which is not far from the mean of that in case of the six 
Dmx 

deeper lakes. In Canadice Lake — =0.64, a number nearlv one-third higher than 

Dmx 

the mean of the other lakes and about 16 per cent greater than the highest one. This 
fact is of great influence on the heat supply of Canadice Lake. 

Both lakes are small and shallow as compared with those which have been discussed. 
Their mean temperature is correspondingly high (Otisco, 19. 2°; Canadice, 15. 8°). Both 
temperatures, and especially that of Otisco, are much above that of the deeper lakes. 
The mean depth, however, is so small that the total amount of wind-distributed heat, 
Dm (Tm s -4), is much smaller. In Canadice this sum is 19,400 gram-calories per square 
centimeter of surface, and in Otisco Lake the amount is still smaller, 17,000 gram- 
calories. It appears therefore that Canadice Lake accumulates about 80 per cent as 
much heat per unit of surface as the larger lakes and Otisco Lake about 65 per cent 
as much. 



A UMNOI^OGICAI, STUDY OF THE FINGER LAKES. 573 

No discussion of these facts would be possible if it was based on the single series of 
ooservations made on each of these lakes, but these can be interpreted in the light of 
the almost innumerable observations on Wisconsin lakes, and considered in this light 
they are extremely interesting. 

The influence of the small size of the lake is apparent in the shallow epilimnion — 
7 meters, or a little more than half its thickness in the larger lakes. The same general 
relation is shown by other similar facts. The temperature of the lower water is raised 
above 4 by mixture; and the depth at which this water reaches temperatures of io° 
or 1 5 in August will give, like the position of the thermocline, the approximate value 
of the mixing power of the wind. In 1910 the temperature of 15 lay at about 10 meters 
in Canadice Lake, 11 meters in Otisco, 18.5 meters in Cayuga, 15 meters in Seneca and 
Owasco. The temperature of io Q lay at 14 meters in Canadice, from 20 to 25 meters in 
the other lakes. In Otisco the bottom water at 20 meters had a temperature of 12 . 
The bottom of the epilimnion marks the lower limit of the direct distribution of heat in 
summer, and its position in the various lakes is the best measure of the relative influence 
of the wind on them. The depth of the successive isotherms also marks the approximate 
levels of wind influences. As would be expected, these levels are higher in the smaller 
lakes, and their smaller dimensions form the first reason for their smaller gain of heat. 

The second reason lies in the smaller mean depth of the lake and the smaller reduced 
thickness of each stratum. In a shallow lake the heating surface is greater in proportion 
to the depth than in a deeper lake, and it might therefore be expected that the former 
lake would be proportionately higher in temperature, and that the number of calories 
gained per square centimeter of surface would be the same in the two lakes so that the 
product Dm (Tm E -4) would be nearly constant for all lakes as it is for those of the first 
class. It might be expected, for instance, that if Canadice Lake (Dm =16.4 meters) 
gained 19,400 calories of wind-distributed heat, then in Otisco Lake, with a mean depth 
of 1 1. 2 meters, Tm s -4 would be high enough to make the product about the same, so 
that the two lakes would gain the same amount of heat from an equal heating surface. 
This might be expected the more readily as Otisco is the larger lake and has a relatively 
larger surface; but so far from reaching this result, Otisco Lake has gained only about 
17,000 calories, or nearly 9 per cent less than the deeper lake. 

There are two reasons for this disadvantage of a shallow lake. First, the tem- 
perature of the epilimnion is determined not only by the relation of insolation and wind 
action, but even more by losses to the air. A shallow epilimnion ordinarily reaches a 
higher temperature than a thicker one, but the difference in the temperature is not so 
great as in the reduced thickness, so that the total amount of heat in the epilimnion is 
smaller. The losses to the air prevent the temperature from rising above a certain 
point. If, for instance, the epilimnion of Canadice Lake were to have as much heat as 
even that of Keuka, whose epilimnion is the thinnest of the six major lakes, Tm-4 
would have to be 22. 3 , and Tm 26. 3 . This is an obviously impossible temperature 
as the mean of any considerable stratum, since in our latitudes it is reached only by 
a very thin surface layer in the hottest part of bright calm days. It rarely persists 
overnight. 



574 BULLETIN OF THE BUREAU OF FISHERIES. 

This difference between the deep and shallow lakes, however, is relatively less 
apparent in the epilimnion than in the thermocline and hypolimnion. In these regions 
the second disadvantageous factor of the shallower lake comes in with more influence. 
The gains of heat of the water in and below the thermocline depend wholly on mechanical 
mixture. There are no gains from the sun and no losses to the air and practically no 
losses by conduction. Hence the thermal resistance to mixture a is the factor which 
resists the transfer of heat downward, and the influence of the wind, direct or indirect, 
is the force which carries the heat down. But the thermal resistance increases much 
more rapidly than the temperature rises and soon puts an end to the force of the wind 
in carrying the heat downward. If we compare the thermocline of Otisco and Canadice 
Lakes, we find that the region is included between the same levels in both lakes and that 
the temperature is not greatly different (Canadice, 12. 9 ; Otisco, 13. 2°). The advantage 
in temperature is on the side of the shallower lake. But the reduced thickness of the 
region in Otisco Lake is only 3.05 meters as against 3.76 meters in Canadice. The 
total amount of heat in the region is therefore about 17 per cent less. 

If the thermocline of Otisco Lake were to derive as much heat from each square 
centimeter of surface as did that of Canadice, Tm-4 for that region must be 15. 7 , or 
2. 5 above that actually reached. A great amount of energy is needed to produce this 
increase from 13. 2° to 15. 7 by mixture. The increase of temperature is about 19 per 
cent but the work to be done in effecting this increase is much greater than that. 

The work to be done in warming a stratum of water which lies below the direct 
influence of the sun is done against gravity which resists the descent of the warmer and 
lighter water. The net work done in warming a stratum of water to a given degree 
may be measured by the energy which would be needed to transport the mass of water, 
thus warmed, to the place where it is found, against the resistance of denser water at a 
temperature of 4 . We may think of such a stratum as pushed down to its place through 
water at 4 , somewhat as a sheet of cork might be forced down through the water. The 
weight to be moved is the difference in weight between the warmed water and water at 
the temperature of maximum density. The distance through which it is carried is the 
mean distance of the stratum in question from the surface. 

In this case the difference in the amount of work necessary to warm the thermo- 
cline to 13. 2 and 15. 7 is proportional to the difference in loss of weight of water at 
these temperatures. A liter of water at 13. 2 weighs 621 milligrams less than at 4 , 
and this is the weight of each liter to be used in computing the work done in warming 
the thermocline. At 15. 7 the weight of a liter is 982 milligrams less than at 4 . Thus 
over one-half must be added to the work which was done in warming the water to 13.2 , 
if 2.5 , or about 19 per cent, are added to the heat. 

A similar statement may be made for the hypolimnion. If this region in Otisco 
Lake is to receive as many calories per square centimeter of the surface of the lake as 
does that of Canadice, its temperature will rise to 12 . But to effect this rise would 
require, if measured on the same basis as in the former example, more than three times 

°Birge, Edward A.: An unregarded factor in lake temperatures. Transactions Wisconsin Academy of Sciences, vol. xvi, 
pt. 2, p. 989. 1910. 



A LJMNOLOGICAL, STUDY OF THE FINGER LAKES. 



575 



as much work as that which was actually available for warming it. This is obviously 
a demand impossible to satisfy. 

Thus the shallow lake has a double disadvantage. Its smaller reduced thickness 
for any given stratum diminishes the volume of water into which heat may be distributed 
from the surface. This deficiency of volume can not be compensated by an equivalent 
rise of temperature, since the amount of energy present to mix the water is soon ex- 
hausted by the rapid rise of thermal resistance to mixture as the temperature increases. 

The shallow lake has an advantage in one respect, probably a small advantage but 
one whose amount has not been determined. What may be called its mixing areas are 
more efficient because of the gradual slope of the bottom. Consider the condition of the 
lake with direct thermal stratification, whose form is that of an oblong tank with vertical 
sides. A wind blowing the surface water to one end would depress the isotherms there. 
The cold water would swing back and oscillate, but there would be very little friction 
between the strata and little mixture and correspondingly little warming of the lower 
water. In an actual lake with sloping bottom, the narrower ends concentrate and give 
force to the movements of the water caused by the wind and increase the amount of 
mixture due both to the direct and indirect effects of the wind. As the warm water is 
forced downward at the ends, it squeezes out the cooler water in a relatively thin layer 
between the descending surface of the epilimnion and the gradually sloping bottom of 
the lake. As the cool water swings back, its edge pushes in like a wedge between the 
bottom and the epilimnion. Both movements are attended with relatively great fric- 
tion and corresponding mixture of the warmer and cooler water. Thus the ends of the 
lake constitute its chief mixing areas, and they are the region where the gradual warming 
of the thermocline and hypolimnion goes on most rapidly. Relatively little warming is 
effected in the open water of the lake or on its steep sides where movement, which is 
chiefly lateral, is attended with little resistance and consequent mixture. In this respect, 
therefore, the shallow lake has an advantage over the deeper one whose slopes are steeper. 
The shallowness of the water is also an advantage in the spring before the thermocline 
is formed, in that the water is nearer the surface and so more readily accessible to the 
influence of the wind. Thus its temperature rises above that of the deeper lake, but it 
never reaches a point, under conditions otherwise equal, high enough to give it as great 
a total amount of heat per unit of surface as the deeper lake accumulates. 

Table XIV. — Extent, Reduced Thickness, and Heat Supply of the Thermal Regions op 

Canadice and Otisco Eakes. 



Region. 



Extent, 
meters. 


R. T. 

meters. 


Tme-4. 


Calories. 


0-7 


6-33 


18.2 


xi, soo 


7-12 


3-76 


12.9 


4,800 


12-25 


6.28 


4-93 


3,100 


0-7 


5-57 


18.8 


10, 500 


7-12 


3- OS 


13-2 


4,000 


12-20 


2.58 


8.4 


2, 200 



Per cent. 



SS.8 
24.8 
16. 2 



i>2. 7 
24.1 
12.3 



Canadice Lake, 1970. 

Epilimnion 

Thcrmoelinc 

Hypolimnion 

Otisco Lake, 1910. 

Epilimnion 

Thermocline 

Hypolimnion 



576 BULLETIN OF THE BUREAU OF FISHERIES. 

DISSOLVED GASES. 

METHODS OF OBSERVATION. 

During the month of August, 1910, observations were made on 10 of the Finger 
Lake for the purpose of ascertaining the amount of dissolved oxygen and carbon 
dioxide in their waters. The samples of water for these determinations were obtained 
either by means of a pump and hose or with a closing water bottle. With one excep- 
tion the former method was used at all depths in the shallower lakes — that is, those 
not exceeding 30 meters (100 feet) in depth — and in the upper water of the deep lakes. 
The water bottle was used on Otisco Lake and in the lower strata of the deep lakes. 

The Winkler method was used for the determination of the quantity of dissolved 
oxygen and the Seyler method for the carbon dioxide. These methods have been 
fully described in a previous publication,® and further consideration of them is not 
necessary here. A new table of oxygen saturations (table xxi, p. 609) is included 
as a substitute for the previous one. It is based upon the more recent determinations 
of Fox, & who gives the results for degrees centigrade from — 2° to +30 . The inter- 
vening tenths of degrees have been interpolated. 

OVERTURNING AND CIRCULATION OF THE WATER. 

The Finger Lakes belong to the temperate type, in which the water is subject to an 
overturning and a complete vertical circulation in the autumn and also in the spring. 
These phenomena are such important factors in the general distribution of the dis- 
solved gases that they deserve a brief description here as a preliminary to the discussion 
of the gases. When the surface water begins to cool in late- summer or early autumn, 
it becomes heavier than the water below it and tends to sink, thereby producing con- 
vection currents. Through the agency of these currents and the wind the water of the 
epilimnion is thoroughly mixed, and as the temperature of this stratum declines with 
the advance of the season more and more of the lower water becomes mixed with the 
upper; that is to say, there is a downward movement of the thermocline and the epilim- 
nion becomes thicker at the expense of the hypolimnion. This process continues until 
the temperature of the epilimnion approaches that of the hypolimnion, when the whole 
body of water may be set into rotation by a strong wind. This phenomenon is known 
as the autumnal overturning, and it is followed by a complete circulation of the water, 
which continues until the lake becomes covered with ice. Seneca and Cayuga Lakes 
do not freeze over completely very often — on an average only about once in 20 years — 
so that their waters are subject to disturbance by the wind during the entire winter. 

As long as the temperature of the water remains above 4 in the autumn both the 
4wind and the convection currents are concerned in the production of the circulation, 

<* Birge, Edward A., and Juday, Chancey: The Inland Lakes of Wisconsin: The dissolved gases of the water and their bio- 
logical significance. Wisconsin Geological and Natural History Survey, Bulletin xxii. Scientific Series No. 7, 259 p. 1911. 

& Fox, Charles J. J.: On the coefficients of absorption of the atmospheric gases in distilled water and sea water. Part I. 
Nitrogen and Oxygen. Conseil Permanent International pour L'Exploration de la Mer. Publications de circonstance. No. 41, 
1907, 23 p., 1 pi. 



A LIMNOLOGICAE STUDY OF THE FINGER LAKES. 577 

but below that temperature the former is the only active agent. When the surface 
water cools below 4 it becomes lighter than the warmer water beneath it and tends to 
float on the latter; that is, there is a resistance to mixture owing to the difference in 
their temperatures. As a result, it requires a strong wind to disturb the water to any 
considerable depth. But in spite of this resistance to mixture the wind is able to disturb 
the water at all depths, even in the deepest lakes, and cause the late autumn and 
winter temperatures to fall well below 4 . (See table iv, p. 555.) The winter stratifi- 
cation is inverse; that is, the coldest water is at the surface and the warmest at the bottom. 

In spring conditions again become favorable for an overturning and circulation of 
the water. In the lakes which freeze over in winter a preliminary step in this process 
is the removal of the covering of ice. Substantially all of the direct warming takes place 
close to the surface, and as the temperature rises this water becomes heavier than that 
below and tends to sink, thus producing convection currents; but this holds true only 
as long as the temperature remains below 4 or the point of maximum density. After 
the whole body of water reaches a temperature of 4 any warming of the surface layer 
makes it lighter than the cooler water below and it tends to float on the latter. This 
eliminates convection currents as a factor in producing a general circulation, but they 
still play a more or less important role in mixing the water of the upper stratum when 
cooling takes place at the surface at night or during cool periods. The wind is now 
the only agent involved in the production of a complete vertical circulation. 

As the season advances the temperature of the upper water rises so that it offers 
a greater and greater resistance to mixture with the cooler water below. As a conse- 
quence the tendency of the lower water to take part in the circulation grows correspond- 
ingly smaller and smaller. Finally the thermal resistance to mixture becomes so great 
that the wind is no longer able to mix the warm upper water with the cooler water below 
and the lake becomes separated into three distinct strata, viz, the epilimnion, the 
thermocline, and the hypolimnion. (See p. 547.) This is known as a direct thermal 
stratification, and it persists from early summer until the autumnal overturn takes place. 

The autumnal circulation is much more thorough than the vernal. This is due to 
the fact that the mere cooling of the water in the autumn, as long as its temperature 
is above 4 , produces convection currents which tend to mix the various strata. In 
the spring, however, general convection currents are formed only as long as the water 
remains below 4 , which is generally only a comparatively short period of time. Small, 
spring-fed lakes, in fact, in which the temperature of the bottom water rises to 4 before 
the ice disappears, and which are well sheltered from winds, may not experience a 
complete vernal overturning under favorable weather conditions. 

OXYGEN. 

Circulation periods. — During the autumnal and vernal periods of vertical circulation 
all of the dissolved gases, as well as other substances that may be held in solution, are 
uniformly distributed from surface to bottom; but during the succeeding stages there 



578 BULLETIN OF THE BUREAU OF FISHERIES. 

may be marked changes in the gaseous content of the different strata. As the water 
cools in the autumn its capacity for oxygen increases, and free exposure to the air enables 
it to obtain additional amounts of this gas as circulation proceeds. As a result, the 
lakes enter the winter stage of their cycle substantially saturated with oxygen at all 
depths; that is, with about 9.0 cc. to 10.0 cc. per liter of water. No winter observations 
were made on the Finger Lakes, but it is safe to assume from the results obtained on 
Wisconsin lakes that there is little change in the quantity of oxygen in the deeper lakes 
during the winter, more especially in those which show only a comparatively small 
decrease in the lower water in summer. In winter the life processes which furnish 
decomposable material are at a low ebb,, and the temperature of the water is so low that 
decomposition goes on very slowly, even at the bottom, where organic material may be 
fairly abundant. In the shallower lakes, however, there may be a marked decrease of 
dissolved oxygen in the bottom stratum, and under favorable conditions it may even 
disappear entirely from some of the lower water. 

At the close of the vernal period of vertical circulation the oxygen has a fairly 
uniform distribution from surface to bottom, but more or less marked changes take place 
in the different strata during the direct stratification stage, so that the history of the 
dissolved gases is different for the different zones. The maximum difference is found 
during August, and for this reason a single set of observations during this month, such 
as made on the Finger Lakes, makes it possible to give the history of the dissolved 
gases with a very considerable degree of accuracy for the whole stratification period. 

In the epilimnion. — As already noted, the epilimnion is kept in circulation by the 
wind, which tends to keep the quantity of dissolved oxygen near the saturation point. 
But the amount is subject to variations in spite of this fact. As the temperature of 
the epilimnion rises in spring and early summer its capacity for holding oxygen in solution 
decreases so that the volume of this gas tends to decrease until the summer maximum 
of temperature is reached. But the loss of oxygen may not keep pace with the rise 
in temperature. That is, a certain quantity in excess of the amount required for satura- 
tion may remain for a while, since the water tends to retain the residual gas unless it is 
pretty thoroughly agitated by the wind. In such instances, however, the quantity 
of excess oxygen is never very great. This stratum is preeminently the zone of photo- 
synthesis and in this process some oxygen is liberated by chlorophyllous organisms. If 
the epilimnion is well populated with such organisms and the conditions are favorable 
for photosynthesis this stratum may become supersaturated with the oxygen that is 
liberated. Another small amount is obtained from the nitrites and nitrates which 
serve as a source of nitrogen for the chlorophyllous organisms. 

The appended table (table xvin, p. 602) shows that at the time of these observations 
the epilimnion of all of the Finger Lakes contained between 6 and 7.4 cc. of dissolved 
oxygen; with the exception of Conesus Lake it was a little larger than the amount 
required for saturation, the maximum excess being about 12 per cent. In most of the 
lakes a larger portion or perhaps all of this excess oxygen was most probably due to 
the photosynthetic activities of chlorophyl-bearing organisms since they were well 



A IylMNOEOGICAL STUDY OF THE FINGER LAKES. 579 

populated with such forms. But in some of the larger and deeper lakes a portion or 
possibly all of the excess may have been due to the presence of residual gas, more espe- 
cially since some of them, such as Owasco and Seneca, had a relatively small number 
of chlorophyllaceous organisms. 

In addition to the processes which tend to keep the volume of oxygen at or above 
saturation in this stratum, there are others which tend to reduce it below that point. 
A certain amount is consumed in the respiration of the various organisms inhabiting 
this region, and another portion, perhaps much larger, is removed by the decomposition 
of organic material. The amount of oxygen actually held in solution by this water then 
is the resultant of the processes which tend to maintain an abundant supply and those 
which tend to exhaust it. If consumption exceeds the new supply, the amount falls 
below the saturation point as in Conesus Lake ; but if the factors which tend to maintain 
saturation and to raise the amount above this point predominate, the opposite result 
is produced. 

In the hypolimnion. — During the period of thermal stratification, the hypolimnion 
is cut off from contact with the air by the epilimnion and conditions are not favorable 
for photosynthesis in this stratum. As a result the only source of oxygen during this 
time is the small amount which diffuses down from the upper water. But this gas 
diffuses very slowly through water, its coefficient of diffusion being only 1.62, so that 
only a small and negligible amount is obtained in this way. Thus the supply of dis- 
solved oxygen of the lower water is limited to the amount which it possesses at the close 
of the vernal period of circulation. Any decrease during the summer remains as a 
deficiency until the autumnal overturn takes place and the normal amount is not regained 
until after complete autumnal circulation is established. 

As might be expected from the above conditions, different lakes show wide differences 
with respect to the quantity of dissolved oxygen in the hypolimnion in late summer; 
but they readily fall into three groups. The first includes those lakes in which some 
or practically all of the hypolimnion is devoid of free oxygen in the later stage of the 
stratification period; the second comprises those lakes in which there is a marked 
decrease of dissolved oxygen in some or all of the hypolimnion but not an actual disap- 
pearance of it; and the third class includes those lakes in which the decrease of the 
oxygen in this stratum is comparatively slight. These differences in the dissolved 
oxygen content depend, in the main, upon two factors, viz, the amount of decomposition 
taking place in the hypolimnion (which may be characterized as the zone of decompo- 
sition) and upon the volume of this stratum. If the epilimnion contributes a large 
amount of decomposable material in the form of dead plankton organisms to the lower 
water and the volume of the hypolimnion is relatively small, most or practically all of 
the dissolved oxygen in the stratum may be consumed before the autumnal overturning. 
Before the oxygen all disappears, some of it is also consumed in the respiration of organ- 
isms which may occupy this region, such for example as fishes and plankton Crustacea. 
But decomposition is a much more important factor in the removal of oxygen from this 
stratum. 



5 8o 



bulletin of the; bureau of fisheries. 



Conesus and Otisco Lakes are good representatives of this class. In the former all 
of the water below a depth of 10 meters either possessed no free oxygen at all or con- 
tained only traces of it. The same was true of a few meters of the bottom water of 
Otisco Lake. (See table xviii, p. 602, fig. 9 and 10.) The oxygen disappears from the 
bottom water first because decomposable material is more abundant at that depth. This 
material is derived from plankton organisms and from shallow water and shore vege- 
tation. The specific gravity of the plankton organisms is so low that they sink 

through the cool, lower water 

*» ,- rf f "-f 1 ' V T f " f ? "" 'I *T^*f '7 f ^. ' very slowly and they thus pass 

through the earlier stages of 
decomposition at least before 
they reach the bottom. In this 
way they draw upon the oxy- 
gen supply at all depths in the 
hypolimnion so that, if such 
decomposing organisms are. 
sufficiently numerous and the 
volume of this stratum is not 
too great, practically all of the 
dissolved oxygen may disappear 
from this region. 

If the decomposable ma- 
terial derived from the epilim- 
nion is not so abundant, or if 
the volume of the hypolimnion 
is relatively great, with a cor- 
respondingly large amount of 
oxygen, there is not a total 
exhaustion of this gas in any of 
this stratum, but only a marked 
decrease, such as was noted in 
Canadice and Hemlock Lakes. 
(See table xvin, p. 602, and 
fig. 11 and 12.) Here the water 
below 18 meters contained less 
than 50 percent of the quantity of oxygen required for saturation; the bottom water 
in the latter lake had as little as 8.4 per cent. 

If a still smaller quantity of decomposable material is derived from the upper 
water, or if the volume of the hypolimnion is still larger, the decrease of oxygen is 
correspondingly smaller, as in Canandaigua, Cayuga, Keuka, Owasco, Seneca, and 
Skaneateles Lakes, which belong to the third class. (Table xviii, p. 602, and fig. 13-18.) 
Perhaps Keuka Lake should be placed in the second class, since its bottom water con- 
tained less than two-thirds of the amount of oxygen required for saturation; but it 



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Fig. 9. — Conesus Lake, Aug. 23, 1910. The curves for dissolved gases are desig- 
nated as follows: C=carbon dioxide; that portion to the left of the zero line 
indicates the alkalinity and that to the right the free carbon dioxide; 
Cb=fixed carbon dioxide; 0=oxygen; and T=temperature. The vertical 
spaces represent the depth in meters and the horizontal spaces show the 
temperature in degrees centigrade and the cubic centimeters of gas per liter 
of water at normal temperature and pressure. The depths at which obser- 
vations were made are indicated by small circles and these points have 
been connected directly without any attempt to round off the curves. 



A LIMNOIvOGICAI, STUDY OF THE FINGER EAKES. 



5«"i 



has been placed in the third class because it belongs to the group of major lakes in 
other features. 

The minimum amount of oxygen in these lakes was found at the bottom, and it 
varied from 5.57 cc. per liter of water in Keuka Lake to 8.45 cc. in Seneca Lake, or 
from 63.8 to 91.7 per cent of saturation. It will be noted that all of the members of 
this class are the larger and deeper lakes of the group— that is, those that have been 
designated as the major lakes. The volume of the hypolimnion of each is relatively 
large in comparison with the epilimnion, very large indeed in the deepest ones, and this 
large body of cool water is able to hold in solution a proportionally large quantity of 
oxygen, so large that the respiration of the organisms inhabiting it and the decomposi- 
tion of the organic material which _ _ 

sinks into it from the upper water do 
not make extensive inroads upon the 
supply of free oxygen. The mem- 
bers of the first and second classes 
constitute the group of minor lakes. 
They are relatively small and shal- 
low bodies of water, in which the vol- 
ume of the epilimnion is large in pro- 
portion to that of the hypolimnion. 

How large a proportion of the 
oxygen supply of the hypolimnion is 
lost during the summer depends 
upon the amount consumed in respi- 
ration and decomposition and upon 
the volume of this stratum. If the 
volume of the epilimnion is relatively 
large in proportion to that of the hy- 
polimnion and it is well populated 
with plankton organisms, so that it 
contributes a large amount of de- 
composable material to the latter, the dissolved oxygen is rapidly consumed, so that 
very little may be left in this stratum by midsummer. On the other hand, when the 
hypolimnion is relatively very large and the upper water contributes only a compara- 
tively small amount of decomposable material, the total volume of oxygen suffers only 
a very small decrease. 

In the thermocline. — The quantity of dissolved oxygen in the thermocline is dependent 
in the main upon the amount in the hypolimnion. If it is practically exhausted from 
the lower water, there is generally a rapid decrease of oxygen as we pass downward 
through the thermocline. In Conesus Lake, for example, the amount decreased from 
6.0 cc. per liter of water at 8 meters to o.n cc. at 10 meters. In Otisco Lake it declined 
from 5.77 cc. at 9 meters to 0.34 cc. at 12 meters. (See table xvm, p. 602.) But lakes 



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Fig. 10. 



-Dissolved gases, Otisco Lake, Aug. 16, 1910. 
see fig. 9, p. 580. 



For explanation, 



582 



BULLETIN OE THE BUREAU OP FISHERIES. 



belonging to this class may have a large excess of oxygen in the thermocline; as much 
as 20.0 cc. per liter or more have been found in some of the small lakes of Wisconsin. 

In lakes of the second class there may be either an appreciable decrease of oxygen 
in the thermocline, as in Green Lake, Wis., or the amount may be larger than that 
found in the epilimnion or the hypolimnion, as in Canadice and Hemlock Lakes. The 
oxygen curves of the latter lakes (fig. n and 12) show that the maximum amount of 



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Fig. 



-Dissolved gases, Canadice Lake, Aug. 24, 
For explanation, see fig. 9, p. 580. 



Fig. 12. — Dissolved gases, Hemlock Lake, Aug. 23, 1910. 
For explanation see fig. 9, p. 580. 



this gas was obtained in the thermocline, a small excess being present there. This 
increased quantity doubtless represented oxygen that had been liberated in this stratum 
by chlorophyllaceous organisms. 

In the third class of lakes there was a larger quantity of oxygen in the thermocline 
than in the epilimnion, owing to the fact that this water was cooler, hence capable of 
holding a larger amount in solution. (See fig. 13-18.) 



A LIMNOLOGICAL STUDY OF THE FINGER LAKES. 



583 



CARBON DIOXIDE. 



Carbon dioxide is readily soluble in water, but the total amount that may be found 
in a lake water depends chiefly upon the quantity of other substances present with which 
it is most generally combined. It exists in three different states. A part of it is in 
close chemical union with substances that are dissolved in the water, more especially 
calcium and magnesium, forming the carbonates of these substances. This is known 
as the fixed carbon dioxide. Another is in a 
fairly loose combination with the carbonates, 
converting them into bicarbonates. This con- 
stitutes the half -bound carbon dioxide. A third 
portion exists in an uncombined or free state, 
and is known as the free carbon dioxide. 

Fixed carbon dioxide.- — The quantity of fixed 
as well as of half -bound carbon dioxide depends 
upon the amount of calcium and magnesium 
that may be present in the water, and the 
amount of these substances, in turn, is dependent 
upon their relative abundance in the drainage 
basin. The normal carbonates of calcium and 
magnesium are only slightly soluble in pure 
water. Rainwater absorbs carbon dioxide from 
the air, and obtains still more from decomposing 
organic matter when it reaches the earth. When 
this water, which is charged with more or less 
free carbon dioxide, comes into contact with 
these normal carbonates, they are freely con- 
verted into bicarbonates, which readily pass into 
solution. Thus, if the water which falls upon 
the adjacent land and reaches the lake either 
by surface drainage or by percolating through 
the ground and finally emerging as a spring, 
comes into contact with an abundance of calcium 
and magnesium carbonates on its journey, the 
lake water will possess a relatively large amount 
of bicarbonates, and it will be classed as "hard" 
water. If, however, the inflowing water comes into contact with very small amounts 
of these normal carbonates, the quantity of bicarbonates will be small, hence the lake 
water will be "soft." 

This serves to explain why there is such a marked difference in the quantity of fixed 
carbon dioxide in the waters of the Finger Lakes. It varied from a minimum of 6.8 cc. 
per liter of water in Canadice Lake to 24.0 cc. in Canandaigua Lake. (See table xvni, 
p. 602, and fig. 9-18.) In Hemlock Lake the fixed carbon dioxide amounted to 12.9 cc, 



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Fig. 13.- 



-Dissolved gases, Keuka take, Aug. 18, 
For explanation see fig. 9, p. 580. 



5»4 



BULLETIN OF THE BUREAU OF FISHERIES. 



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Fig. 14. — Dissolved gases, Canandaigua Lake, Aug. 20, 1910. 
For explanation see fig. 9, p. 580. 



in Keuka Lake, 16.8 cc, while in the 
other lakes it varied from 21.0 to 24.0 cc. 
In Conesus and Otisco Lakes there was an 
appreciable increase of this gas toward 
the bottom; in the former the bottom 
water contained 5.1 cc. more than the 
surface and in the latter 7.3 cc. 

A much greater range in the quantity 
of fixed carbon dioxide has been found 
in the waters of the Wisconsin lakes. 
In them the amount varies from a mini- 
mum of 1.0 cc. to a maximum of about 
50.0 cc. 

Half-bound carbon dioxide. — In neutral 
waters and in those which possess free 
carbon dioxide the half-bound carbon 
dioxide is assumed to be equal in amount 
to the fixed. But in waters which give 
an alkaline reaction with phenolphtha- 
lein there is an excess of fixed carbon 
dioxide which equals in amount the de- 
ficiency of the half -bound. From a bio- 
logical standpoint the half -bound carbon 
dioxide is of very great importance since 
it serves as a source of carbon dioxide 
for the photosynthetic activities of chlo- 
rophyllous organisms. From four-fifths 
to five-sixths of it may be consumed in 
this process, but none of the fixed car- 
bon dioxide is available. The free car- 
bon dioxide may be consumed by the 
algae, but if found at all in the upper 
water it is present very generally in rela- 
tively small amounts. 

Free carbon dioxide. — There are four 
sources of free carbon dioxide in lake 
waters. They are the atmosphere, de- 
composition of organic material, the 
respiration of organisms, and spring or 
ground waters. This gas constitutes a 
small portion of the atmosphere, from 
three to four parts per 10,000, so that 
where a water is freely exposed to the 



A LIMNOLOGICAE STUDY OF THE FINGER LAKES. 



585 



air it will be found to contain some free carbon dioxide. The amount, however, 
is small because it is absorbed only in proportion to its partial pressure. The decay of 
organic matter yields considerable carbon dioxide and, under favorable conditions, the 
water may become charged with fairly large amounts derived from this source. This 
is true especially of the bottom water. Spring waters are generally charged with free 
carbon dioxide, so that they contribute their quota. 



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Fig. is- — Dissolved gases, Cayuga Lake, Aug. 11, 1910. 
explanation see fig. 9, p. 580. 



For 





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Fig. 16. — Dissolved gases, Owasco Lake, Aug. 13, 1910. For 
explanation see fig. 9, p. 580. 



The quantity of free carbon dioxide in the epilimnion is subject to variations. 
The water of this stratum is kept in circulation by the wind and this process tends to 
maintain a normal amount of this gas; but the quantity derived from the respiration 
and the decomposition which take place in this layer tends to raise it above the satu- 
ration point. On the other hand, this region is preeminently the zone of photosyn- 
thesis and in this process carbon dioxide is consumed and oxygen is liberated. When 
this stratum is fairly well stocked with chlorophyllous organisms and conditions are 



5 86 



BULLETIN OF THE BUREAU OF FISHERIES. 







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Fig. 17. — Dissolved gases, Seneca Lake, Aug. 4, 1910. For 
explanation see fig. 9, p. 580. 



Fig. 18. — Dissolved gases, Skaneateles Lake, Aug. 15, 
1910. For explanation see fig. 9, p. 5S0. 



A UMNOLOGICAE STUDY OF THE FINGER LAKES. 587 

favorable for their activities, the demand for carbon dioxide exceeds the supply of free 
gas and some of the half-bound carbon dioxide is consumed. This makes the water 
alkaline to phenolphthalein, since it leaves an excess of normal carbonate. The degree 
of alkalinity is measured by the amount of carbon dioxide that would be required to 
convert this normal carbonate to bicarbonate, and it is dependent upon several factors, 
chief among which are the free exposure to the atmosphere, decomposition, respira- 
tion, the abundance and activity of the algae, and the weather conditions. Thus it 
will be seen that the status of the carbon dioxide in the epilimnion is the resultant of 
the activities of those agents which furnish a supply to this stratum and those which 
consume this gas. 

The epilimnion in all of the Finger Lakes was alkaline, thus showing that not only 
the free, but also some of the half-bound carbon dioxide, had been consumed by the 
chlorophyl-bearing organisms. (See table xviii, p. 602, and fig. 9-18.) The degree of 
alkalinity varied in the different lakes, ranging from a minimum of about 0.5 cc. in 
Canadice Lake to a maximum of 3.0 cc. in Canandaigua Lake; in five lakes the average 
amount was about 2.5 cc. In the carbon dioxide curves the alkaline stratum is indi- 
cated by that portion which lies to the left of the zero line and the degree of alkalinity 
is shown by the quantity of carbon dioxide required to make the water neutral. 

The free carbon dioxide content of the thermocline depends upon the conditions 
which are found there for photosynthesis. In some lakes this stratum lies so near the 
surface that light conditions are favorable for this process and in such cases not only 
the free, but a large portion of the half-bound carbon dioxide may be removed by chloro- 
phyllous organisms, thus making the stratum strongly alkaline. But in a large majority 
of cases conditions in this stratum are not favorable for photosynthesis and the water 
contains free carbon dioxide. This was true of all of the Finger Lakes. 

The hypolimnion is a zone of decomposition, so that its water generally contains 
an abundance of free carbon dioxide. In the process of respiration also a certain 
amount of this gas is contributed to the water and some may reach this stratum from 
underground waters. The largest amount is found at the bottom of the lake, where 
decomposition is greatest owing to the presence of a large amount of organic material. 
The maximum quantity found in the bottom waters of the Finger Lakes varied from 
1.0 cc. per liter in Cayuga Lake to 7.1 cc. in Hemlock Lake. 

PLANKTON. 

Methods of observation. — Plankton catches were obtained in the Finger Lakes at the 
same time that samples of water were procured. They were made either by means of a 
pump and hose or with a vertical closing net. The former method was used at all 
depths in Canadice, Conesus, and Hemlock Lakes, and in the upper 30 meters and 50 
meters, respectively, of Cayuga and Seneca Lakes, while the latter method was employed 
below these depths in the last two lakes and at all depths in the other five lakes. For 
the purpose of counting, a catch was diluted to 10 cc, of which 2 cc. were removed 
with a "stempel" pipette, and the Crustacea and rotifers therein were counted. When 
46512°— 14 5 - 



588 



BULLETIN OF THE BUREAU OF FISHERIES. 



only a small number of the larger Crustacea were present, the total number in the catch 
was determined by direct count. One cubic centimeter of the diluted material was 
then placed in a Sedgwick-Raf ter counting cell, and the protozoa and algae were enumer- 
ated in the usual manner. The results were reduced to the number of individuals per 
liter of water, and the diagrams were platted on this basis. For table xix the number 
of planktonts per liter was multiplied by a thousand in order to give the number per 
cubic meter of water. 

Distribution of plankton organisms. — The vertical distribution of the various plankton 
organisms in the five lakes on which pump catches were made is shown in the accom- 





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Fig. 19. — Vertical distribution of plankton organisms in Canadice Lake, Aug. 24, 1910. Scale, 1 vertical space=i meter; 1 
horizontal space=s Crustacea, nauplii, and rotifers, and 100 algae and diatoms per liter of water. Predominant forms: 
Cyclops, Diaplomus, Ceraiium, and Aslerionella. The column at the right marked O shows the quantity of dissolved 
oxygen at the various depths as indicated, and T represents the temperature. 

panying diagrams (fig. 19-23). These figures show the usual distribution of the 
chlorophyl-bearing portion of the plankton. That is, such organisms are confined 
chiefly to the epilimnion, where light conditions are most favorable for their photosyn- 
thetic activities. So much of the sun's energy is absorbed by the upper meters of water 
that only a very small portion generally penetrates as far as the thermocline and the 
hypolimnion, thus making these regions unfavorable for the forms which depend upon 
light for the manufacture of an important element of their food. But in some of the 
small lakes of Wisconsin, which are well protected from wind, the top of the thermocline 
lies at such a slight depth — only 3 to 4 meters below the surface — that enough light for 
the process of photosynthesis reaches this stratum. This is shown by the large excess 
of oxygen that is sometimes found in this layer. 



A UMNOLOGICAE STUDY OF THE FINGER LAKES. 



589 



Some of the plankton algae appear to be able to live saprophytically, and such forms 
could maintain themselves in this manner in the deeper water. Oscillatoria seems to 
show this tendency most frequently, and one of its usual distributions was shown in 
Keuka Lak'e, where the maximum number was found in the 15-20 meter stratum. (See 
table xix, p. 606.) In general, however, the presence of large numbers of phytoplank- 
tonts below the thermocline is to be regarded as an indication of their senility. 

The curves for zooplankton show two general types of vertical distribution. In one 
type the lower, as well as the upper, strata of the lake are well populated, as in Canadice 
and Hemlock Lakes (fig. 18, 19). A similar distribution was noted also in Keuka and 





























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Fig. 20. — Vertical distribution of plankton organisms in Hemlock Lake, Aug. 23, 1910. Scale, 1 vertical space=i meter; 1 hori- 
zontal space=5 Crustacea, nauplii, and rotifers per liter of water and 130 algae and diatoms. Predominant forms: Diaptomus, 
Ceratium, Coelosphcerium, and Aslerionella. The column at the right marked O shows the quantity of dissolved oxygen at 
the various depths as indicated, and T represents the temperature. 

Owasco Lakes. All of the various forms of plankton animals were not distributed 
throughout the depth of these lakes, since some of them habitually occupy the warmer 
water of the epilimnion, while others are confined chiefly to the thermocline and the 
hypolimnion. In the latter stratum the crustacean population consisted almost entirely 
of Diaptomus and Cyclops and their nauplii, while Polyarthra platyptera had the widest 
vertical distribution among the rotifers. In general, the forms which have a wide 
vertical distribution reach their maximum numbers either in the upper or the middle 
strata of the lake. The presence of a fairly large population in the lower water is 
dependent upon two factors, viz, an adequate amount of both dissolved oxygen and food 



59° 



BULLETIN OF THE BUREAU OF FISHERIES. 



in this region. Whenever the quantity of either falls below a certain amount, it affects 
the distribution of the organisms. 

The second type of vertical distribution is characterized either by a very sparse 
population in a certain portion of the hypolimnion or by practically none at all. This 
is due either to a lack of dissolved oxygen or to a scarcity of food. In Conesus and 
Otisco Lakes, for example, the absence of organisms in the lower strata was caused by a 
lack of oxygen. (See fig. 20.) Results obtained on Wisconsin lakes show that the 
various zooplankton forms are capable of occupying water which has only a very small 
amount of dissolved oxygen, but a certain minimum quantity is necessary. The Clado- 
cera and Diaptomi are only rarely found in water which has less than 0.2 to 0.3 cc. per 
liter, while the minimum for Cyclops and nauplii is about 0.1 cc, and for rotifers from 























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Fig. 21. — Vertical distribution of plankton organisms in Conesus Lake, Aug. 25, 1910. Scale, 1 vertical space=i meter; 1 horizon- 
tal spaee=io Crustacea, nauplii, and rotifers per liter of water and 100 algae and diatoms. Predominant forms: Cyclops, 
Polyarthra, Ceratium, Caelospheerium, Fragilaria. The column at the right marked O shows the quantity of dissolved 
oxygen at the various depths as indicated, and T represents the temperature. 

0.1 to 0.2 cc. Several forms, however, such as Corethra larvae, an ostracod, and a number 
of protozoa are able to live in water which contains no trace of free oxygen ; but all of the 
limnetic zooplanktonts, except larval Corethra, require at least a small amount of this 
gas in a free state. 

In Conesus Lake the maximum number of Diaptomi was found at 9 meters, where 
the water contained 1.5 cc. of oxygen per liter. Cyclops and the nauplii reached their 
maximum numbers at a depth of 10 meters, where this gas amounted to only 0.11 cc; 
only a few remained at 12 meters, where the quantity of oxygen was only 0.06 cc, and 
none was found below this depth. 

In Cayuga and Seneca Lakes (fig. 21 and 22) by far the larger portion of the hypo- 
limnion had a very sparse population, being occupied by only a few Crustacea, repre- 
sentatives of Cyclops, Diaptomus, and Limnocalanus , between 50 meters and the bottom. 



A LIMNOIyOGICAI, STUDY OF THE FINGER LAKES. 



591 



But the bottom stratum was more densely populated, possessing a larger number of 
Limnocalanus macrurus, as well as a small population of Mysis relicta. A similar dis- 
tribution of the crustacea in the lower water was found also in Canandaigua and Skane- 
ateles Lakes. 

The limiting factor in these lakes was not the lack of dissolved oxygen in the lower 
water, since there was an abundance of it even at the bottom, but it was a scarcity of 
food. The chlorophyl-bearing portion of the plankton is the primary source of food for 
the rotifers and the crustacea, either directly or indirectly, and, as noted above, these 
organisms are confined chiefly to the epilimnion. This means substantially that the 



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Fig. 22. — Vertical distribution of plankton organisms in Cayuga Lake, Aug. 12, 1910. Scale, 1 vertical space=s meters; 1 hori- 
zontal space= 10 crustacea, nauplii, and rotifers per liter of water and 600 algae and diatoms. Predominant forms: Bosmina, 
Polyarthra, Ceralium, and Asterionella. The column at the right marked O shows the quantity of dissolved oxygen at the 
various depths as indicated, and T represents the temperature. 



zooplankton, not only of the upper water, but also at all other depths, is dependent upon 
the food supply of the epilimnion. The zooplanktonts which occupy the epilimnion have 
the first choice of this food, and those in the hypolimnion must be content with that 
which reaches them from the upper water. 

Granting that the lower water has an abundance of dissolved oxygen, the density 
of its population depends upon the food supply, which, in turn, is dependent upon the 
excess produced by the epilimnion and upon the volume of the hypolimnion. The 
excess of food produced by the upper water depends upon the productivity of that stratum 
and upon the amount consumed by the zooplankton therein. The largest excess of 



592 



BULLETIN OF THE BUREAU OF FISHERIES. 



course will be obtained from a large population of chlorophyl-bearing organisms and a 
small number of consumers. With a given amount of excess food the relative abundance 
depends upon the volume of the hypolimnion; the larger the volume of the water the 
smaller the relative abundance of food, and vice versa. 

These two types of vertical distribution have been noted also in the Wisconsin 
lakes. Only a comparatively small number of these bodies of water show the first type 
of distribution. Among those showing the second type the scarcity or absence of rotifers 
and Crustacea in the lower strata is due in all cases to the lack of oxygen, with the excep- 
tion of Green Lake, in which an insufficient supply of food is the important factor. 

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Fig. 23.— Vertical distribution of plankton organisms in Seneca Lake, Aug. 4, 1910. Scale, 1 vertical space=s meters; 1 horizontal 
space=5 Crustacea, nauplii, and rotifers per liter of water and 100 algae and diatoms. Predominant forms: Cyclops, Poly- 
arthra, Ceratium, and Asterionella. Below 90 meters the organisms were too few to indicate in the diagram. The column at 
the right marked O shows the quantity of dissolved oxygen at the various depths as indicated, and T represents the 
temperature. 

Taking into account the results obtained both on the Wisconsin lakes and on the 
Finger Lakes, it appears that when the hypolimnion is well populated the maximum 
depth of the lake does not exceed 40 to 50 meters. On the other hand, when the maxi- 
mum depth reaches 70 meters or more a certain portion of the hypolimnion has a sparse 
population. The upper part of this stratum may possess a fairly large population, since 
it lies near the source of the food, and the bottom stratum may also be fairly well popu- 
lated, but between these two regions lies a zone which is poor in zooplankton, owing to 
the scarcity of food. The thickness of this poorly populated zone depends upon the 
maximum depth of the lake and also upon the relative amount of food contributed to 
the hypolimnion by the upper water. 



A UMNOLOGICAIv STUDY OF THE FINGER LAKES. 593 

The Finger Lakes differ widely in area, depth, gas content, etc., but there was no 
corresponding qualitative difference in the plankton. For the most part the same 
forms were present in all of the lakes, but the relative abundance of the various forms 
varied greatly in the different lakes. The most prominent qualitative differences were 
the absence of Daphnia in Seneca Lake and the absence of Limnocalanus and Mysis in 
the smaller and shallower lakes. 

Phytoplankton. — Three different classes of alg3e were represented in the plankton 
of the Finger Lakes, viz, the Chlorophyceae by Staurastrum; the Bacillarieae or diatoms 
by Melosira, Cyclotella, Tabellaria, Fragilaria, Synedra, Asterionella, and Navicula; and 
the Myxophyceae, or blue-green algae by Anabaena, Aphanizomenon, Lyngbya, Oscil- 
latoria, Ccelosphaerium, Clathrocystis , Gloeocapsa, and Aphanocapsa. These forms were 
confined chiefly to the epilimnion where light conditions were most favorable for the 
process of photosynthesis. In some of the lakes, however, relatively large numbers of 
phytoplanktonts were found in the thermocline and even in the upper portion of the 
hypolimnion. In Cayuga Lake, for example, there were more than a thousand Asterio- 
nellas per liter of water at a depth of 30 meters and in Skaneateles Lake this same form 
numbered 1,161 per liter in the 30-50 meter stratum, more than five times as many as 
were found in the 0-10 meter stratum. The presence of this form in such large numbers 
in the deeper water where light conditions were not so favorable for photosynthesis was 
most probably due to the fact that they were senile individuals. Both lakes had a fairly 
high degree of transparency, a Secchi's disk disappearing from view at a depth of 5.1 
meters in Cayuga Lake and at 10.3 meters in Skaneateles Lake, but it is doubtful whether 
enough light reached these organisms to enable them to carry on the process of photo- 
synthesis to any considerable extent. 

The circulation of the water of the epilimnion tends to produce a uniform dis- 
tribution of the phytoplankton in this stratum, but the diagrams (fig. 18-22) indicate that 
such a result was not attained, since all of the curves representing algae show a point 
of maximum density of population. 

In Canandaigua and Otisco Lakes the blue-green algae predominated, with Clath- 
rocystis and Ccelosphcerium as the most abundant forms. Clathrocystis was the pre- 
dominant alga in Owasco Lake. Diatoms were most abundant in the other seven 
lakes, with Asterionella, Fragilaria, and Tabellaria as the predominant forms. 

Zooplankton. — Ceratium was found in all of the Finger Lakes, and was most abun- 
dant in Cayuga, where 2,525 individuals per liter of water were found at the surface. 
Hemlock Lake ranked second, with a maximum number of 1,645 individuals per liter 
at a depth of 12 meters. The smallest number was found in Owasco Lake, and Seneca 
Lake came next in order. Owing to the fact that this is a chlorophyllous organism, 
it has been included in the curves showing the blue-green algae in the diagrams. 

Dinobryon appeared in the plankton of 7 of the 10 lakes, but it was scarce in 
all except Owasco, where it was much more abundant than any of the other small 
organisms. 



594 BULLETIN OF THE BUREAU OF FISHERIES. 

Mallomonas was found in three lakes, viz, Canadice, Conesus, and Otisco. In 
Canadice and Otisco Lakes it showed the peculiar distribution which has been noted by 
Whipple;" that is, it was found only in a middle stratum in the lake. In the former 
lake it was found almost exclusively in the 10-15 meter stratum, only a few being at 
the bottom. There was a maximum number of 2,110 individuals per liter of water at 
10 meters. In Otisco Lake it was confined to the 9-12 meter stratum, while in Conesus 
Lake it occupied only the epilimnion or 0-8 meter stratum. 

Colonies of Vorticella, attached to colonies of Anabaena or some other alga, were 
found in small numbers in Canadice, Cayuga, Conesus, and Seneca Lakes. The largest 
number was noted in a surface catch from Cayuga Lake, 13 colonies per liter of water. 
In all of these lakes except Seneca, Vorticella was confined to the upper 10 meters or less, 
a few being noted at 1 5 meters in the latter lake. 

Among the rotifers Polyarthra was the only form which was found in all of the 
lakes. It was most abundant in Cayuga Lake. One catch showed an average of 240 
individuals per liter in the 0-5 meter stratum. Next in order were Seneca Lake, with 
an average of 23 individuals per liter in the upper 15 meters, and Conesus, with an average 
of 23 for the upper 8 meters. In all cases Polyarthra was more abundant in the 
epilimnion than below this stratum. 

Anuraea cochlearis was present in all but three lakes, Conesus, Owasco, and Skan- 
eateles. It was not as abundant as Polyarthra. The largest catch showed only 53 indi- 
viduals per liter. This catch was obtained in Cayuga Lake at a depth of 20 meters. 
Seneca Lake was next in order, with a maximum number of 40 per liter of water at 5 
meters in one evening catch. In all of the other lakes no catch showed more than 4 
individuals per liter. In both Cayuga and Seneca Lakes Anuraea cochlearis was found 
chiefly in the upper 20 meters of water. 

Asplanchna likewise was most abundant in Cayuga and Seneca Lakes. The 
maximum number of 26 individuals per liter of water was found at a depth of 5 meters 
in Cayuga Lake, while a catch at this same depth in Seneca Lake showed 15. A very 
few individuals were found in Keuka, Owasco, and Skaneateles Lakes, and none in the 
other lakes. It was confined chiefly to the epilimnion. 

Notholca longispina was present in all of the lakes except Owasco and Skaneateles. 
The largest number, 4 per liter, was found at a depth of 1 2 meters in Hemlock Lake. 

Conochilus was found in all except three lakes, Canadice, Conesus, and Otisco, 
but it was present in very small numbers and always in the epilimnion. 

Anuraea aculeata appeared in the catches from five lakes, but its maximum number 
was less than 3 individuals per liter of water. 

The catches from Cayuga and Seneca Lakes contained a few Ploesoma, the largest 
number being 6 per liter. 

A few specimens of Triarthra were found in Cayuga, Hemlock, and Keuka Lakes. 

In counting the copepods no attempt was made to enumerate the different species 
of Diaptomus and Cyclops separately. The former genus was represented in all of the 

"Whipple, G. C, Microscopy of drinking water, p. 109. New York, 1899. 



A UMNOIvOGICAL STUDY OF THE FINGER LAKES. 595 

lakes. Two species, D. minutus and D. sicilis, were found in Cayuga and Seneca Lakes, 
but only the former species was present in the other lakes. In its vertical distribution, 
Diaptomus was found at all depths where the water contained a sufficient amount of 
dissolved oxygen. In Conesus and Otisco Lakes it did not occupy the bottom water, 
owing to the absence of oxygen, but the maximum number in both was obtained just 
above the low oxygen zone. The largest number in Conesus Lake, 43 individuals per 
liter, was found at 9 meters where the water contained 1.5 cc. of oxygen, but the number 
fell below 1 per liter at 10 meters where the water contained only 0.11 cc. of free oxygen 
per liter. In Otisco Lake the largest number was found in the 9-12 meter stratum 
where the oxygen decreased from 5.8 cc. at 9 meters to 0.34 cc. at 12 meters. 

The largest catch of Diaptomus was obtained at the surface of Canadice Lake, 
48 individuals per liter. This was a rather unusual distribution, since this form usually 
avoids a few meters of the upper water in the daytime. The second largest catch was 
that on Conesus Lake, noted above. In Seneca Lake the maximum number, 20 per 
liter, was found at 50 meters. In both Seneca and Cayuga Lakes, Diaptomus showed 
a diurnal movement of about 10 meters. 

Representatives of the genus Cyclops were found in all of the lakes. In Seneca and 
Cayuga Lakes this form was most abundant in the upper 50 meters, although it extended 
to the bottom. In some lakes, however, it was confined entirely to the upper water. 
In Canandaigua Lake it was not found below 15 meters; in Skaneateles Lake, not below 
the 20-30-meter stratum; and in Owasco Lake, not below the 10-15- meter layer. This 
was a rather unusual distribution, since in general Cyclops seems to experience no 
difficulty in occupying much deeper water than is found in these lakes. Their absence 
from the lower water was not due to a scarcity of dissolved oxygen, because there was an 
abundance of it in the bottom water of these lakes, in fact almost or quite as much as 
at the surface. 

In Keuka Lake Cyclops was most abundant in the upper 10 meters, but in Canadice 
and Hemlock Lakes it was distributed rather uniformly from surface to bottom. In 
Conesus Lake its distribution was similar to that which has been found frequently 
in some of the Wisconsin lakes, viz, a fairly uniform distribution in the epilimnion 
with a maximum number in the thermocline, where there is a rapid decrease of the 
oxygen. The maximum number, 62 per liter, was found at 10 meters, where the dis- 
solved oxygen amounted to only 0.11 cc. per liter. But in Otisco Lake, where there 
was also a rapid decrease of dissolved oxygen in the thermocline, no such phenomenon 
was found, there being a fairly uniform distribution in the epilimnion with only a small 
number below this stratum. 

Limnocalanus in small numbers was found in five lakes — Cayuga, Seneca, Canan- 
daigua, Skaneateles, and Owasco. It was confined to the hypolimnion, or lower stratum, 
of all of these lakes. A very few specimens of Epischura were obtained in Keuka and 
Owasco Lakes. 

The copepod nauplii showed great diversity in their vertical distribution. They 
were found at all depths in the majority of the lakes, but they were more abundant 



596 BULLETIN OF THE BUREAU OF FISHERIES. 

in the upper strata, say, in the upper 20 or 30 meters of the deeper lakes and in the upper 
10 or 15 meters of the shallower ones. There was one marked exception to this. In 
Canadice Lake the maximum number was found at a depth of 20 meters, within 4 meters 
of the bottom. In Conesus and Otisco Lakes the distribution was similar to that which 
has been found in some of the Wisconsin lakes. That is, the maximum number was 
found in the thermocline, where there was only a small amount of dissolved oxygen. 
For example, there were 123 individuals per liter at a depth of 10 meters in Conesus 
Lake where the oxygen amounted to only 0.11 cc. per liter of water. 

The cladoceran population of Seneca Lake was characterized by the absence of 
Daphnia and by the relative abundance of Bosmina. The latter occupied the upper 
50 meters of water and the largest number, 31 individuals per liter, was found at a 
depth of 5 meters in an evening catch. The only other Cladocera represented in the 
plankton catches of Seneca Lake were Ceriodaphnia and Polyphemus pediculus, but 
only a very small number of each was found. Daphnia was absent from the regular 
plankton hauls on Cayuga Lake, but a few specimens of D. hyalina were found in one 
of the townet catches. Bosmina was found at all depths in Cayuga Lake, but it was 
most abundant in the upper 30 meters. The maximum number, 66 individuals per 
liter of water, was obtained in a morning catch at a depth of 10 meters. Ceriodaphnia 
and Polyphemus pediculus were also represented in the plankton of Cayuga Lake, but 
they were not noted in any other lakes. 

Daphnia longispina var. hyalina was represented in all of the lakes except Seneca. 
It was confined chiefly to the epilimnion of the various lakes and was most abundant in 
Hemlock Lake. Daphnia pulex was present in Canadice and Conesus Lakes. It was 
scarce in the former but a little more abundant than D. hyalina in the latter. 

A few Daphnia retrocurva were found in the 12-meter catch of Hemlock Lake. 

Diaphanosoma was noted in Canadice, Canandaigua, Hemlock, Otisco, Owasco, 
and Skaneateles Lakes, and was confined to the epilimnion. It was most abundant in 
Canandaigua Lake, where it averaged about three individuals per liter in the upper 
15 meters. 

Bosmina was obtained in all of the lakes except Canadice, Conesus, and Otisco. It 
was most abundant in Cayuga Lake and Seneca came next. Only a relatively small 
number was obtained in the other five lakes. 

A few specimens of Leptodora hyalina were found in each of the lakes except Conesus 
and Seneca. 

Specimens of Mysis relicta were taken with townets in the lower water of Canandaigua, 
Cayuga, Keuka, and Seneca Lakes. 



A LIMNOLOGICAL STUDY OF THE FINGER LAKES. 



597 



APPENDIX.— STATISTICAL TABLES. 

HYDROGRAPHIC DETAILS OF THE NEW YORK LAKES. 

In tables xv and xvi are given the details of the hydrography of the New York lakes. The figures 
are given both on the metric system and on the foot and mile system (table xvi). All measurements 
and all primary computations are made on the metric system. The areas given for the lake basins at 
25 feet, 50 feet, etc., are derived not from replatting the soundings and drawing a new set of contours, 
but from the hypsographic curves constructed from the measurements on the metric system. 

In the tables on the metric system columns 2-4 give the areas of the lake basin and the length of 
contours at the depths stated in column 1. In the subsequent columns the areas, volumes, and slopes 
are those between the depths stated in column 5. 

Volumes are usually stated to tenths of a million cubic meters. 

The formulas used in computation will be found on p. 538. 

The general results of the hydrography are given in table 1, p. 537. 

Table XV. — Hydrographic Details. 
CANADICE LAKE 







Length 














Depth. 


Area. 


of 


Depth. 


Area. 


Volume. 


Slope. 






contours. 




























Thousand 








Meters. 


Sq. km. 


Per cent. 


Km. 


Meters. 


Sq. km. 


Per cent. 


cu. m. 


Per cent. 


Per cent. 


1 





2.60 


100. 


11.7 


0-2. 5 


0.274 


10. 6 


6,154 


14-5 


10. 1 


5 46 


2-5 


2.32 


89 


4 


10.4 


2-5-5 


.144 


5-5 


5,632 


13.2 


17-9 


10 09 


5 


2.18 


81 





10.1 


5-ro 


.202 


7-9 


10, 402 


24-4 


24. 6 


13 49 


10 


1.98 


7° 





9.77 


10-15 


.345 


13-2 


9,034 


21. 2 


14. 


7 59 


IS 


1.63 


62 


8 


8.62 


15-20 


.368 


14.1 


7,251 


17.0 


11. 


6 17 


20 


1.27 


48 


7 


7.52 


20-22. 5 


.329 


12.7 


2,753 


6-5 


5-37 


3 04 


22. 5 


.94 


*S 





6.59 


22.5-25.4 


.936 


36.0 


1,351 


3.2 


1-45 


50 


25 

25.4 


.14 






2.61 
































2.60 


42,577 



















OTISCO LAKE. 
[Measurements to causeway near south end.] 






6.84 


100. 


16.6 


0-5 


2.07 


30-3 


28,850 


37-7 


3-5 


2 


02 


5 


4.77 


69.7 


12.7 


5-10 


0.67 


■ 9.8 


22,160 


20.0 


18.5 


10 


29 


10 


4.10 


59-9 


12.1 


io-is 


0.58 


8. 5 


19,040 


24-9 


io.; 


11 


02 


15 


3.52 


Si- 5 


10.5 


15-20. 1 


3.52 


51-5 


6,390 


8.4 


I-S 





52 


20. 1 


0.0 








































6.84 


76, 440 



CANANDAIGUA LAKE. 

















Million 






















CU. VI. 











42.3 


100. 


57.2 


O-IO 


10.4 


24.4 


362.2 


22. z 


5-1 


2 55 


5 


35.4 


81 


7 


50.5 


10-20 


3.19 


7.8 


302.6 


18.4 


14.7 


8 22 


IO 


31.9 


75 





48.2 


20-30 


2.98 


7.0 


271.7 


16.5 


15-6 


8 52 


20 


28.7 


07 


8 


46.5 


30-40 


2.98 


7-1 


241.2 


14.7 


IS- 2 


8 39 


30 


25.7 


60 


8 


46.3 


40-'50 


4.07 


0.6 


206.3 


12.6 


10.7 


6 07 


40 


22.7 


53 


7 


44.9 


50-60 


6.36 


15-0 


153.4 


9-4 


5-9 


3 22 


50 


18.6 


44 


1 


42.4 


60-70 


7.85 


18.6 


80.2 


4-9 


2. I 


1 15 


60 


12.3 


20 





32.7 


70-80 


4.32 


10. 2 


22.2 


1.4 


1.9 


1 05 


70 


4.42 


10 


1 


15.1 


80-84 


.10 


. 2 


.12 


. 


■3 


10 


75 
80 
83-5 


1.99 


4 


7 


9.5 
















.10 




1.6 








































42.3 




1640. 1 





















598 



bulletin OE the; bureau of fisheries. 



Table XV. — Hydrographic Details — Continued. 
CAVUGA LAKE. 







Length 
















Depth. 


Area. 


of 


Depth. 


Area. 


Volume. 


Slope. 






contours. 






























Thousand 








Meters. 


Sg. km. 


Per cent. 


Km. 


Meters. 


Sq. km. 


Per cent. 


CU. VI. 


Per sent. 


Per cent. 


/ 


o 


172.1 


100.0 


153.8 


O-IO 


47.4 


27.5 


1,435.7 


15-4 


2.9 


1 40 


5 


138.7 


78. 9 


116.5 


10-20 


12.7 


7-4 


1,183.4 ■ 


12.6 


7-6 


4 21 


IO 


124.8 


72-5 


100.9 


20-30 


8.0 


4.6 


1,080.2 


II- S 


II- 5 


6 34 


20 


112.0 


65.1 


93.3 


30-40 


10.1 


5-9 


989.6 


10.6 


8.8 


5 02 


30 


104.0 


60. 5 


90.8 


40-50 


12.0 


7.0 


878.7 


9.4 


7-1 


4 04 


40 


93.9 


54-6 


86.4 


50-60 


8.3 


4.8 


777.3 


8-3 


9.9 


5 39 


SO 


81.9 


4.7.6 


83.9 


60-70 


7.8 


4.6 


696.4 


7-4 


10. 


5 43 


60 


73.6 


42.8 


80.4 


70-80 


7.1 


4-1 


622.0 


6.6 


10. 6 


6 03 


70 


65.8 


38.2 


76.3 


80-90 


8.0 


4-6 


546.8 


5-8 


8. 9 


5 05 


80 


58.7 


34-1 


72.4 


90-100 


8.4 


4.9 


464.8 


5-0 


7-6 


4 21 


90 


50.7 


29.5 


68.9 


ioo-no 


8.4 


4.9 


380.5 


4-1 


6.6 


3 47 


100 


42.3 


24.6 


58.2 


I 10-120 


17.9 


10. 4 


244.2 


2.6 


2.6 


1 30 


no 


33.9 


10.7 


53.9 


120-130 


15.3 


8.9 


79.1 


0.8 


1-5 


52 




16.0 


0-3 
4-3 
0.4 


39.4 


130-133 


0.8 


0.4 


0.7 






34 




7.4 


30.3 












130 


0.8 


6.2 
















132- 6 


0.0 






































172.2 


9,379.4 



KEUKA LAKE. 






47.0 


100.0 


111.2 


O-IO 


7.30 


15-6 


432.6 


30.2 


12.4 


7 04 


IO 


39.7 


84.4 


99.5 


10-20 


5.49 


11. 7 


368.8 


25-7 


17.7 


10 02 


20 


34.2 


72.8 


95.8 


20-30 


7.79 


16.6 


302.0 


21. I 


11. 7 


6 40 


30 


26.4 


$6.2 


86.4 


30-40 


11.30 


24.0 


204.7 


14-4 


6.1 


3 29 


40 


15.1 


32-1 


50.4 


40-50 


7.92 


16. 


108.8 


7.4 


5-3 


3 02 


So 


7.17 


IS- 2 


35.8 


50-57 


7.17 


15-2 


16.7 


1.2 


1.4 


48 


SS-8 


0.0 




































* 


47.0 


1,433.7 



OWASCO LAKE. 

















Million 






















cu. m. 











26.7 


100. 


41.6 


O-IO 


5.38 


20. I 


238.3 


30- S 


7-3 


4 11 


IO 


21.3 


79-8 


37.3 


10-20 


4.27 


16. 


191.3 


24- S 


8-3 


4 44 


20 


17.0 


63.8 


33.9 


20-30 


2.41 


9.0 


158.1 


20.3 


13-2 


7 36 


30 


14.6 


54.8 


20.0 


30-40 


4.37 


16. 4 


122.8 


15-7 


6.0 


3 26 


40 


10.2 


38-4 


22.1 


40-50 


6.57 


24. 6 


66.9 


8.6 


2.7 


1 33 


So 


3.68 


13.8 


13.7 


So-54 


3.68 


13-8 


3.31 


0.4 


2.7 


I 33 


54- 










































26.68 


780.7 



SENECA LAKE. 






175.4 


100. 


128.3 


O-IO 


22.6 


12. 9 


1,639.7 


io.6 


5-4 


3 05 


IO 


152.8 


87.1 


115.1 


10-20 


11.1 


6-3 


1,472.6 


9-5 


10.2 


5 50 


20 


141.7 


80.7 


111.2 


20-30 


7.6 


4-3 


1,378.7 


8.9 


14. 


7 58 


30 


134.1 


76-3 


109.6 


30-40 


8.1 


4.6 


1,300.4 


8.4 


13-5 


7 41 


40 


126.0 


71.8 


108.4 


40-50 


9.2 


5-2 


1,214.1 


7-8 


11. 8 


6 44 


So 


116.9 


66.6 


107.2 


50-60 


10.0 


5-7 


1,113.9 


7-2 


10. s 


6 00 


60 


106.9 


60.8 


102.6 


60-70 


6.9 


4.0 


1,034.1 


6.6 


14.6 


8 18 


70 


100.0 


56.9 


100.5 


70-80 


6.3 


3-5 


968.1 


6.2 


16. 1 


9 09 


80 


93.7 


53-3 


99.9 


80-90 


8.1 


4.6 


896.0 


5-8 


12. 1 


6 34 


90 


85.6 


48.8 


94.8 


90-100 


6.0 


3-4 


826.0 


5-3 


IS- 7 


8 55 


100 


79.6 


45-3 


92.3 


ioo-no 


5.7 


3-2 


767.9 


4.9 


IS- 8 


8 58 


no 


73.9 


42. 1 


89.1 


IIO-I20 


5.7 


3-2 


713.3 


4.6 


15-4 


8 45 


120 


68.2 


38.9 


86.5 


I2O-I3O 


6.4 


3-7 


649.8 


4.2 


13- 1 


7 28 


130 


61.8 


35-2 


82.9 


I3O-I40 


11.7 


6. 7 


558.5 


3-6 


6.6 


3 48 


140 


50.0 


28. S 


73.1 


I4O-I5O 


10.2 


5-8 


448.5 


2.9 


6.9 


3 57 


150 


39.8 


22.2 


67.8 


I50-160 


12.6 


7-2 


333.2 


2. 1 


4-9 


2 47 


160 


27.2 


15-5 


55.0 


160-170 


15.7 


8.9 


188.0 


1.2 


2.8 


1 35 


170 


11.5 


6-5 


32.4 


I70-I80 


9.3 


5-3 


62.3 


0.4 


2.4 


1 21 


180 


2.2 


1.2 


11.6 


180-188 


2.2 


1.2 


4.3 


0.03 


1-7 


1 00 


188 


0.0 






































175.4 


15, 539. 5 



A LIMNOLOGICAL STUDY OF THE FINGER LAKES. 

Table XV. — Hydrographic Details — Continued. 
SKANEATELES LAKE. 



599 









Length 














Depth. 


Area. 


of 


Depth. 


Area. 


Volume. 


Slope. 








contours. 




























Thousand 








Meters. 


Sq- km. 


Per cent. 


Km. 


Meters. 


Sq. km. 


Per cent. 


cu. m. 


Per cent. 


Per cent. 


/ 


o 


35.9 


100.0 


52.0 


O-IO 


8.82 


24-5 


314.0 


20. 1 


5-51 


3 09 


IO 


27.1 


75-5 


45.2 


10-20 


2.93 


8.2 


256.3 


16.4 


15. 1 


8 35 


20 


24.2 


'67-3 


43.8 


20-30 


2.42 


6.7 


229.4 


14-7 


17.7 


10 02 


3° 


21.7 


60.5 


42.0 


30-40 


2.14 


6.0 


206.5 


13.2 


19.2 


10 52 


40 


19.6 


54-6 


40.3 


40-50 


2.84 


7-9 


181.6 


11.6 


13-9 


7 55 


5° 


16.8 


4.6.7 


38.9 


50-60 


2.80 


7.8 


153.8 


0.8 


13.9 


7 55 


60 


14.0 


38-Q 


36.1 


60-70 


3.65 


10.2 


121.1 


7-7 


9-1 


5 12 


70 


10.3 


28.7 


30.3 


70-80 


5.05 


14. 1 


76.4 


4-9 


6.1 


3 29 


80 


5.26 


14.6 


31.0 


80-85 


2.95 


8.2 


18.4 


1. 2 


3-9 


2 14 


85 


2.31 


6.4 


14.6 


85-90. 5 


2.57 


6.4 


5.3 


0.3 


1-7 


58 


90 


0.03 


.008 


0.8 






























36.1 


1,562.8 



Table XVI. — Area and Volume of the Lakes in Miles, Acres, and Feet. 

canadice lake. 



Depth. 


Area. 


Depth. 


Area. 


Volume. 
















Million 




Feet. 


Sq. mi. 


Acres. 


Per cent. 


Feet. 


Acres. 


Per cent. 


cu.ft. 


Per cent. 





1.00 


642 


100. 


0-25 


130 


20.3 


677 


45- z 


25 


.80 


512 


79-8 


25-50 


108 


16.8 


492 


32.7 


50 


.63 


404 


62.9 


50-75 


187 


29.1 


322 


20.4 


75 


.34 


217 


33-8 


75-83 


217 


33-8 


14 


.9 


83 


































642 


1,505 



CANANDAIGUA LAKE. 






16.3 


10, 440 


100. 


0- 50 


2,890 


27.7 


19,390 


33-3 


50 


11.8 


7,550 


72.3 


50-100 


1,250 


12.0 


14, 460 


24. Q 


100 


9.84 


6,300 


60. 2 


100-150 


1,260 


12.0 


12,240 


21.0 


150 


7.87 


5,040 


48.3 


150-200 


2,200 


21. 1 


8,925 


IS- 3 


200 


4.44 


2,840 


27.4 


200-250 


990 


9.5 


3,045 


5.2 


250 


2.90 


1.850 


•7-7 


250-274 


. 1,850 


17-7 


130 


. 2 


274 


































10,440 


58,190 



CAYUGA LAKE. 






66.4 


42,520 


IOO. 


0- 50 


13,440 


31-6 


77,465 


23.2 


50 


45.4 


29,080 


68.3 


50-100 


3,490 


8.2 


59,460 


17.8 


zoo 


40.0 


25, 590 


60. 2 


100-150 


4,100 


9.6 


51,160 


'5- 3 


150 


33.6 


21,490 


SO. 6 


150-200 


3,500 


8.2 


42,940 


12.9 


200 


28.1 


17,990 


42-3 


200-250 


2,820 


6.7 


36, 070 


10. 9 


250 


23.7 


15,170 


3S-7 


25o-3oo 


2,910 


6.8 


29,815 


8.9 


300 


19.2 


12,260 


28.8 


300-350 


3,170 


7-S 


23, 165 


6.9 


350 


14.2 


9,090 


21.4 


350-400 


5,980 


14.1 


11,065 


3-3 


400 


4.90 


3,110 


7-3 


400-435 


3,110 


7-3 


1,628 


■4 


435 


































42,520 


332,788 



6oo 



BULLETIN OF THE BUREAU OF FISHERIES. 



Table XVI. — Area and Volume of the Lakes in Miles, Acres, and Feet — Continued. 

keuka lake. 



Depth. 


Area. 


Depth. 


Area. 


Volume. 


Feet. 



50 
100 
'SO 
183 


Sq. mi. 
18.1 
14.2 
9.96 
4.09 


Acres. 

11,610 
9,090 
6,370 
2,620 


Per cent. 
100. 
78.4 
54-9 
22.5 


Feet. 
0- 50 

50-100 
100-150 
150-186 


A cres. 
2,520 
2,720 
3,750 
2,620 


Per cent. 
21.7 
23-5 
32-3 
22. 6 


Million 

cu. ft. 

22,675 

16, 775 

9,380 

1,370 


Per cent. 
45-2 
33-4 
18.7 

2-7 


















11,610 


50,200 



OTISCO LAKE. 





25 
50 

66 


2.64 
1. 71 
1-31 


1,689 

1,094 

839 


100. 
64.8 
40.6 


0-25 
25-50 
50-66 


595 
255 
839 


35-2 
IS-I 
49-6 


1,470 

1,050 

190 


54-3 

38.8 

7.0 


















1,689 


2,710 



OWASCO LAKE. 





S° 

100 

150 
177 


10.3 
7.26 
5.45 
2.47 


6,600 
4,640 
3,490 
1,580 


100. 
70.4 
52.9 
24. 


0- 50 
50-100 
100-150 
iSo-177 


1,960 
1,150 
1,910 
1,580 


20-7 

17.4 
28.0 
24.0 


12 271 

8,965 

5,490 

626 


44-9 

32-8 

20.0 

2-3 


















6,600 


27,352 



SENECA LAKE. 






67.7 


43, 330 


700. 


0-50 


7,120 


16.4 


86,165 


IS- 7 


50 


56.6 


36, 210 


83.6 


50-100 


3,210 


7-4 


75,265 


13-8 


100 


51.6 


33, 000 


76. 2 


100-150 


3,160 


7-3 


66, 725 


12.2 


150 


46.6 


29, 840 


68.0 


150-200 


3,630 


8.4 


60, 980 


II. 2 


200 


41.0 


26, 210 


60. s 


200-250 


3,550 


8.2 


54,210 


9-9 


250 


37.0 


23, 660 


54.6 


250-300 


2,760 


6.4 


48, 305 


8.Q 


300 


32.7 


20, 900 


48.2 


300-350 


2,180 


5-0 


43,110 


7-9 


3 SO 


29.3 


18, 720 


43-2 


350-400 


2,220 


5-1 


38,330 


7.0 


400 


25.8 


16, 500 


38-1 


400-450 


2,410 


5-6 


32, 155 


5-9 


45o 


20.5 


13, 090 


30.2 


450-500 


3,950 


9.1 


24, 100 


4.4 


500 


14.3 


9,140 


21. 1 


500-550 


5,340 


12.3 


13, 050 


2.4 


5 So 


5.84 


3,800 


7-7 


550-600 


2,290 


5-3 


3,410 


0.6 


600 

618 


2.35 


1,510 


0-3 


600-618 


1,510 


3-5 


40 






















43, 330 


545,845 



SKANEATELES LAKE. 




So 
100 
150 
200 
250 
297 


13.9 
9.92 
8.34 
6.95 
5.25 
2.78 


8,900 
6,350 
5,340 
4,450 
3,360 
1,780 


100. 
71-5 
60.2 
SO- 1 
37-9 


0-50 
50-100 
100-150 
150-200 
200-250 
250-297 


2,550 
1.010 
890 
1,090 
1,580 
1,780 


28.6 
II. 4 
10. 
12.3 
17-7 

20.0 


16,495 
12,695 
10, 800 
8,465 
5,480 
1,220 


20.8 

23.0 
19-5 
IS- 6 
9-9 

2. 2 




















8,900 


55,155 



A EIMNOLOGICAL, STUDY OF THE FINGER LAKES. 



60 1 



TEMPERATURE OBSERVATIONS. 

The temperatures observed in 1910 are stated, with the gases, in table xviii, and are shown in 
figures 8-17. The bottom temperatures, stated in table in, are derived from these observations, the 
temperature curve being extended, if necessary, to the deepest water. 

Table; XVII. — Temperature; Observations. 
WINTER TEMPERATURES, 1911, 1912. 



Depth, 
meters. 


Cayuga, 

Feb. 13, 

191 1 ; 

foggy, 

calm. 


Owasco. 


Seneca, 
Feb. 10, 
1911; 
clear, 
light 
south. 


Skaneateles. 


Feb. 11, 

191 1 ; 

snow, ice; 

11 cm. 


Mar. 1, 

1912; 

clear, ice; 

52 cm. 


Feb. 11, 

1911; 
clear, ice; 
6-8 cm. 


Mar. 7, 

1912; 

clear. ice; 

50 cm. 



5 

10 

20 

3° 

40 

50 

60 

70 

80 

90 
100 
105 
160 
Mud .... 


2.00 


0. 10 

.70 
• 70 


0.80 
1.30 
1.30 
1.40 

1. 60 

2. OO 

b 2 . 25 


3-2S 


0. 70 


1. 00 

2. 20 
2. 25 
2. 40 
2. 40 
2. 50 
2. 60 
2. 70 
3- 00 

<*3- 10 


2. 10 


3- 30 
3- 40 


.70 
1. 00 
1. 20 


2-3° 


•75 

.80 

°i. 00 








c i. 20 


2. 50 


















3-4° 
























2- 7S 
















3- 50 








1. 2 


«2- 60 

















SUMMER TEMPERATURES, 19", 1912. 



Depth, 
meters. 


Canan- 

daigua, 

Sept 4, 

1911; 

clear, 

calm; 

mean of 

4 series. 


Cayuga, 
Sept 2, 

1911; 

clear, 
fresh S. 

wind. 


Keuka, 
Sept. s. 

1911; 

part 
cloudy ; 
light S. 

wind. 


Owasco, 
Sept. 3, 

1911; 

clear, 
light N. 

wind. 


Owasco, 

Sept. 13, 

1912; 

clear, 

calm. 


Seneca, 
Sept. 1, 

1911; 

hazy, 
light S. 
or calm. 


Skane- 
ateles, 

Sept. 3, 
191 1 ; 
clear, 
fresh 
NW. 
wind. 


Skane- 
ateles, 
Oct. 18 
1912; 
clear, 
calm. 



5 
10 
11 
12 
13 
14 
IS 
16 
17 
18 
19 
20 
25 
30 
40 
5° 
60 
70 
80 
100 
120 
164 


20. 7 
19.8 
19- S 


20. 


20. 6 
20. 4 
20. 
19- S 
14.9 

12. I 
IO.3 
9.4 


19. 8 
19. 7 
19-5 


19. 6 
19-3 
19. 2 
19. 
18.8 
18.4 
18.3 
18.2 
17.0 
IS- 8 


20. 
19.4 
19. 


19. 6 
19. 6 
19- S 


14. 
13-8 
13- 7 


19.8 


18.3 




19-3 

19. 1 

17-3 

16.6 

15-9 

IS- 4 

13.0 

12- S 

9. 1 

7.6 

6.6 

5-S 

'5-3 


18.8 














19. 6 
19. 
18. S 
16. 1 

13-8 

n- S 

10. 1 

7-9 

S-9 

4.8 

4-5 

4- S 

4.4 

4.2 

4. 1 

'4-1 








15-7 
12. 2 
11. 5 
io. 6 


18.4 
17-3 
14.9 

12-3 

11. 1 
10. 2 
6.8 
S-8 
4-8 
4-3 


19-3 

18.8 
17- S 
16. 4 
14-7 
13-3 
7- 7 
6-5 
S-7 
5-S 


13- 6 


7-3 












7- 7 
S-6 

S-2 

4.6 
4.6 

4.4 

4-3 
"4-3 


6.7 
5-8 
5-6 
5-° 
« 4 .8 


11. 9 
9. 1 

8-3 

7.6 

c 7-3 


13- 5 
13-5 
10.3 
6.8 
6.5 
6.4 

ft 6. 3 








4. 2 
4. 2 
4. I 
4. 1 — 
4. 0+ 


/ 4 . 7 





















































a 51 meters. 
I> 48 meters. 

cOfTMandana. Lake only part frozen. Deeper waternot 
covered by ice. Depth, 51 meters. 
<l 75 meters. 



« 49 meters. 

/ 69 meters. 
9 73 meters. 
* 80 meters. 
i 121 meters. 



602 



BULLETIN OF THE BUREAU OF FISHERIES. 



DISSOLVED GASES. 

The depth is given in meters, the temperature in degrees centigrade, and the gases in cubic centi- 
meters per liter of water. The last column shows the per cent of saturation of the oxygen. In the 
free carbon dioxide, a minus sign indicates that the water was alkaline, a plus sign that it was acid, 
and neut. that it was neutral to phenolphthalein. The degree of alkalinity or acidity is indicated by 
the number of cubic centimeters of carbon dioxide that would have to be added or removed to make 
the water neutral. 

Table XVIII. — Observation on Gases. 



Depth, 
meters. 


Temper- 
ature. 


Carbon dioxide. 


Oxygen. 


Depth, 
meters. 


Temper- 
ature. 


Carbon dioxide. 


Oxygen. 


Free. 


Fixed. 


Cc. per 
liter. 


Per cent 
of sat. 


Free. 


Fixed. 


Cc. per 
liter. 


Per cent 
of sat. 


CANADICE LAKE, AUG. 16, 1910. 


HEMLOCK LAKE, AUG. 23. 1910. 



5 
8 


22.2 
22. 1 
20.6 
19.7 

15-2 

13- 
n. 2 
9-3 
8-5 

8.2 


-0.51 


6.83 


6.50 
6.60 
6.88 
6.98 
7-73 
6.89 
6.13 
5-29 
4.17 
3-37 
2.42 
2.39 


102. 7 
104. 1 
105- 7 
105-6 
107.4 
90-1 

78. S 

64.8 

SO. 2 

40.3 
28.8 
28.4 



5 
8 
9 

10 
12 
15 
18 
24 
27 


21. 7 

21-5 

21.4 
19.8 
18.0 
15-2 
10.9 
9.8 
9-5 
9-3 


—1.80 
—1.80 


12.90 
12.90 


6.77 
6-93 
6. 92 
7.02 
7.42 
7-73 
5-36 
3- 80 
1-37 
0.70 


106.0 


— 0. si 
—0.25 
+0.25 
+0.89 
+1.51 
+2-53 
+3-29 
+4-05 


6.83 
6.83 
6.83 


108. 2 
107.8 
106. s 
108.9 


9 

10 


—1.30 


12.90 
12.90 
12.90 




+0.38 






107.4 




6.83 


68.2 


15 


+3-29 
+5- 06 
+ 7- 10 




47.1 








6.83 


16.8 


20 


12.90 


8-5 


24 


8.0 


+4-45 


6.83 






CANANDAIGUA LAKE, AUG. 20, 1910. 


KEUKA LAKE, AUG. 18, 1910. 




21. 7 
21.3 
20.6 
13- 1 
8.2 
7-6 
6-3 


—3-00 


24.03 


6-75 
6-75 
7.02 
7-83 
7.90 
7.90 
8.10 
8.20 
8.00 
7-13 
6-45 


ios-7 
105.0 
107.9 
104.3 
94.4 
93-1 
92. 6 
93- 
89.9 
80.0 
72. 1 





S 

10 
IS 




5 
10 
15 
20 
30 
40 
51 


21.3 

21-3 

*S-S 
9-7 
8-3 

7-4 


—2.00 
— 1.80 
—0-35 

+ 0.25 

+0.63 

+1. 01 


i6-7S 
16. 75 
i6-7S 
16.75 


6.91 
7-OS 
8.01 
8.10 
7.80 
7-47 
7-51 


107. s 


—3-00 

-1-54 
Neut. 


24.03 

24-54 


109.6 
112. 


25 

30 

40 
60 






+0.5 


24.8 


16.75 


87-6 
87.1 
63.8 




+0.75 
+0.9 
+ 1.26 


24.8 

25-30 
25-60 


6. 4 


+ 2.53 


16.75 


70 








80 


5-4 




CAYUGA LAKE, AUG. 11, 1910. 


OTISCO LAKE, AUG. 16, 1910. 



S 

10 
15 


19.8 
19.6 
19. 6 
19. 2 
15-9 
"■5 
8.6 
7.0 
5-9 
5-i 
4-5 
4-5 
4.4 


— 2.50 


22. 20 


6.6s 
6.8s 
6.84 
7.00 
8.28 
8.27 
8-53 
8.68 
8.80 
8-93 
9-05 
7.92 
7-03 


100.4 
103- S 
103- 3 
105.0 
116. 7 
106.5 
102.9 
100-9 
99.6 
99.1 
98.9 
86.6 
83.2 



5 
8 
9 
10 
11 
12 
IS 
17 


23.0 
22.4 
20. 7 


— 2. 50 
—3-00 

— 2.30 

— 2. 20 
+ 1.01 
+ 2.30 
+2.80 
+3-03 
+3- 80 


21. 00 
21. 00 
21.00 
21.75 
23.50 
25-30 
25.80 
28. 10 
28.30 


6.72 
6.81 
6.70 
5-77 
3.00 
1. 19 
o-34 
0.05 
0.00 


107.7 


— 2. 50 

— 2.50 
— 0.40 
— 0. 40 
Neut. 
Neut. 
+0. 12 


22. 20 
22. 20 
22. 20 
22. 20 
22. 80 


107.9 
103. 1 
85.6 
43-5 
16.6 


18 
20 


17.4 


25 
3° 
40 
5° 


13-5 
12. 6 
12.3 


4-5 

0.6s 

0.0 


22.80 


+0.40 
+0.75 
+ 1.00 






75 
100 
122 




23-3° 
23.8 


OWASCO LAKE, AUG. 13, 1910. 






CONESUS LAKE, AUG. 25, 1910. 




s 

10 
12-5 

15 

17-5 

20 

30 

40 

5° 


21- 5 

20.3 
20.2 

19. 1 
15- 1 
11. 2 
9.8 
7-9 
7-5 
7-i 


—2.50 


22.20 


6.82 
7-03 
6.91 
6.80 
7-97 
7-S6 
7-59 
7- 57 
7.28 
6.82 


106.4 




21.8 
21.6 
21.4 
20.3 
16. 4 
15-5 
14. 6 
13-2 
12.5 


—2.50 


23.02 


6.16 
6. 12 
6. 00 
1.50 
0. 11 
0.0s 
0.06 
Tr. 
0. 00 


96.6 
95-7 
93- S 

22. 9 

1-5 
0.7 
0.8 


107- S 
105-5 














8 
9 


—2. so 
+ 1-77 
+3-03 


23. 02 
24.03 
25.30 


101.8 


—2.50 
+0.50 
+0.63 
+0. 90 
+ 1.26 
+ 1.26 


22. 20 


no. 6 
96-8 
94.1 


10 


' 22. 20 

22. 20 

22. 20 
22. 50 


12 


+3-54 


25-80 
26. 30 
28. 10 


89-9 
85- 6 


17- S 


+4-04 


0.0 


79-5 



A LIMNOLOGICAL STUDY OF THE FINGER LAKES. 
Table XVIII. — Observations on Gases — Continued. 



603 



Depth, 
meters. 


Temper- 
ature. 


Carbon dioxide. 


Oxygen. 


Depth, 
meters. 


Temper- 
ature. 


Carbon dioxide. 


Oxygen. 


Free. 


Fixed. 


Ce. per 

liter. 


Per cent 
of sat. 


Free. 


Fixed. 


Cc. per Per cent 
liter. of sat. 


SENECA LAKE, AUG. 3, 1910. 


SKANEATELES LAKE, AUG. 15, 1910. 



5 


20.2 
19.6 
19.0 

17-2 
11. 6 
8-3 

5-2 

4-6 


—2.50 


22.00 


6.85 
7.00 
7.40 
7.80 
8.40 
8.80 
8.70 
8.90 
9. 00 
9. 10 
8-55 
8-4S 


104.6 
105.7 
no. 6 
112. 8 
108.4 
105.4 
99.0 
97-5 
98.4 
99.2 
93- 
91.7 



5 
10 
15 
20 
25 
30 

SO 

7° 
83 


22.7 
19.8 
17.8 
12. 6 
8.6 


— 1.25 


21.25 


6-75 
7.02 
7- Si 
9- IS 
9. 20 
8.88 
8.77 
8.65 
8.24 
7.89 


107.6 
106.4 
109.8 


—2.50 


22.00 






15 
20 


— 1.25 

—0.5s 
Neut. 
+0.25 
+0.75 


21. 2S 
21. 25 


—1. 00 
—0.50 


22.00 
22.00 


III.O 

104.9 
101.4 
97-9 
92.8 
88.4 


5° 


6.8 
5-9 


21.25 
2I.4O 








Neut. 

+0.25 
+0.40 
+1.26 


22. 00 
22. 20 
22. 20 

22. 20 


130 
150 
J 73 




S-5 


+i. 00 


2I.8o 




4.2 





DISTRIBUTION OF PLANKTON. 

Table xix shows the vertical distribution of the various plankton organisms, giving the number of 
individuals per cubic meter of water at the different depths. The members grouped in the different 
columns are indicated as follows: 1. Cladocera, B=Bosmina, C=Ceriodaphnia, D=Daphnia, Di = 
Diaphanosoma, h=Leptodora, T?=Polyphemus; 2. Copepoda, C=Cyclops, ~D=Diaptomus, ~E=Epischura, 
l,=Limnocalanus; 3. Nauplii; 4. Rotifera, Axi=-Anurcea, As— Asplanchna, C=Conochilus , N= 
Notholca, ¥\=Ploesoma, T?=Polyarthra, T=Triarthra; 5. Protozoa, C=Ceratium, D=Dinobryon, 
M=Mallomonas, V=Vorticella; 6. Green and blue-green algae, An=Anabaena, Ap=Aphanocapsa, 
Aph= A phanizomenon, C=Clathrocystis, Coe=Ccelosphoerium, Q=Gloeocapsa, ~L,=Lyngbya, 0=Oscil- 
latotia, S=Staurastrum; 7. Diatoms, A=Asterionella, C=Cyclolella, V=Fragilaria, M=Melosira, 
'N=Navicula, S—Synedra, T=Tabellaria. 

When present in relatively small numbers, some forms showed an irregular distribution — that is, 
they were not noted at certain depths, but were found both above and below these depths. This does 
not mean, however, that they were entirely absent at the intermediate levels, but that they were not 
found in that portion of the catch which was counted. 

Table XIX. — Analysis of Plankton Catches. 

CANADICE LAKE, AUG. 24, 1910. 



Depth, meters. 


Cladocera. 


Copepoda. 


Nauplii. 


Rotifera. 


Protozoa. 


Green and 

blue-green 

algae. 


Diatoms. 




JO 3,650 
|Di 1,400 

/D 5,000 
\Di 2,100 

(D 2,100 
\Di 2,800 

\l> 700 


C 2,800 
D 48,600 

C 4,200 
D 20, 700 

C 2,100 
D 12,100 

C 2,800 
D 12,800 


700 

5>7oo 
10, 700 

40,000 


I* 1,400 
P 4, 200 


C 252,000 

V 5,700 

C 252,000 

V 2,100 

C 63,300 

V 700 

C 84, 400 
D 108,800 
M 2,110,000 


An 6, 400 
Ap 42,200 
C 189, 000 

C 294,000 
G 63,300 

An 700 
C 168,800 

C 42, 200 
G 42,200 


A 63 , 300 




'* 42, 200 
A 126,600 


8 


T 21,100 
A 189,900 

A 759,6oo 







46512°— 14- 



604 



BULLETIN OF THE BUREAU OF FISHERIES. 



Table XIX. — Analysis of Plankton Catches— Continued. 

CANADICE LAKE, AUG. 24, 1910— Continued. 



Depth, meters. 



Cladocera. 



Copepoda. 



Nauplii. 



Rotifera. 



Protozoa. 



Green and 

blue-green 

algae. 



Diatoms. 



IS- 

iS. 



{» 
{* 
{» 



700 

700 



D 
D 



12,800 



4, 200 
4,200 

2,800 

6,400 
9, 200 



20, 700 
35- 700 

49,200 



An 1 , 400 
N 200 



21. 100 
126,600 



147- 700 
21, 100 



2,100 

2,100 



1,400 
700 



200 
200 



A 1,561,400 
A 400,900 



232. 100 

105.500 

21, 100 

163,300 



CANANDAIGUA LAKE, AUG. 20, 1910. 



40-60, 

60-70. 

70-S0. 



1" 




C 

D 




p. 

iDi 


920 

3,270 


4>5°o 
14,200 


(R 




C 




™ 




3,7O0 


Id. 


2,SOO 


D 


7,200 


[B 




C 
D 




P- 
IDi 


1,300 
2,750 


2,400 
7,600 


I B 


130 






\ U 


130 


D 


4,190 


h 


260 






t 


100 

2,230 
30 


D 
L 


1,640 
460 


[b 


200 


D 


400 


i d 


590 


L 


130 


[b 


230 


D 


360 


p 


25 


L 


100 


{* 


130 


D 


400 
130 


{» 


200 


D 
L 


850 
200 



18,500 



65 



c 
p 


130 
1,300 


c 
p 


130 

2,100 


c 

N 
P 


520 
130 
650 


c 
p 


520 
200 



65 
130 



23, 


200 


92,900 


50,300 


7 


700 


3, 


800 


3 


800 


I 


900 


1 


900 • 


1 


900 



Ap 

C 

S 


11,600 
61,900 
3>8oo 


A 
F 


34,800 
3,800 


Ap 

C 

Coe 


ri, 600 
58.000 
3,800 


A ' 
F 


34,800 
200 


Ap 

C 

Coe 


3,800 
54,200 
23,600 


A 
T 


50,300 
3,800 


An 
Ap 
C 
Coe 


7,700 

7,700 

iS-Soo 

42,600 


A 
T 


2, 100 
1,200 


An 
Ap 
C 
Coe 


1,900 

7, 700 
7,700 
7,700 






Ap 


1.900 






C 
Coe 


1,900 
3,800 


F 


1,900 


Ap 

C 

Coe 


2,900 
2,900 
1,900 


A 
F 
T 


960 
960 
960 


C 
Coe 


1.900 
3,800 






Ap 
Coe 


1,900 
3,800 







CAYUGA LAKE, AUG. 12, i 9 to. 



B 12,800 
C 1,400 



B 32,100 
P 700 



B 65,700 
C 700 



3,500 
1,400 



C 2,800 

D 1,400 



6,400 



An 


35° 


As 


21,400 


P 


100, 700 


An 


ISO 


As 


20.000 


PI 


2.800 


P 


106,400 


An 


S-700 


As 


20,000 


PI 


3,600 


P 


95,700 



,525,000 
15,500 

2,800 



C 1.455,200 
D 15,500 

V 2. 100 



C 1,412,000 
D 15,500 



An 



An 
C 



2,800 



2, 100 
42,800 



42,800 



A 4,494,000 

F 2,011.000 

T 299.600 

A 3,809,000 

F 1,326,800 

T 128,400 



A 4,280.000 
F 2,268.000 
T 214.000 



A UMNOIvOGICAL STUDY OF THE FINGER LAKES. 
Table XIX. — Analysis ok Plankton Catches — Continued, 

CAYUGA LAKE, AUG. 12, 1910— Continued. 



605 



Depth, meters. 



5o-75- 



75-100. 



Cladoeera. 



B 55>"oo 



B 17,100 



B 5,000 



360 



80 



670 



Copepoda. 



c 

D 


700 
1,400 


C 
D 


5.700 
1,400 


C 


4, 200 


D 


1,400 


C 
D 


720 
790 


C 
D 


640 

340 


C 


80 


D 


20 


C 
D 


50 
100 



Nauplii. 



8,500 



Rotifera. 



An 
As 
PI 
P 

An 
As 
P 

An 

N 

P 

An 

N 

P 

An 

N 

P 

An 

N 
P 

An 

N 
P 



2, 100 
24, 200 

5.700 
40,700 

54.400 
12, 100 
21,400 

6,400 

700 

40,000 

200 

100 

2, 100 

50 

50 

630 

30 
30 
630 

90 
30 
180 



Protozoa. 



1, 241,000 
128,400 

428,000 
42,800 
770,400 

299,600 
95,600 

7,600 
1,900 



10,800 



26,300 



15,000 
1,900 



Green and 

blue-green 

algse. 



8, 500 



95,600 



Diatoms. 



A 4,365.000 

F 1,797,600 

T 85,600 

A 1,583,600 

F 1,112,800 

T 642,000 



1,027,000 
470,800 
470, 800 



A 67,500 

F 23,100 

T 27,000 



4T,8oo 
7. 700 
J, 700 

35. 600 

20,000 

7,700 

30,900 
9,600 
15.200 



CONESUS LAKE, AUG. 25, 1910. 





I- 


10,700 


c 


5,000 


8,000 


P 


20, 700 


C 
D 
M 

V 


464, 200 

42, 200 

24,400 

1.400 


An 

Aph 

C 

Coe 

G 


1,400 
42, 200 
84,400 
126, 600 
42, 200 


A 
F 


42, 200 




1,139,400 




f 


















An 


84,400 








r 


7,100 


c 


8,000 


J5>7oo 


N 
P 


700 
25.700 


C 
M 


211, OOO 
42,200 


Coe 
L 


295,400 
42, 200 


A 
F 


42, 200 




1,434,800 




1 


















S 


42, 200 






8 


i° 


4,200 


c 

D 


2,800 
2,800 


9,200 


N 
P 


700 
22, 100 


C 

M 
V 


253,200 

84,400 

2, IOO 


An 
Coe 

S 


2, 100 

717,400 
84,400 


A 
F 


42, 200 




1,899,000 




{» 


5.700 


C 
D 


6,400 

43.500 


38,400 


An 
P 


700 
4, 200 


C 
M 


422,000 
84,400 


Coe 

S 


379,800 
42, 200 


A 
F 


84,400 




1,477,000 




{■> 


50 


C 
D 


62, 100 
700 


122. 80c 


An 

N 
P 


700 

700 

1,400 


C 


337,600 


Coe 

S 


126. 600 
42,200 


F 


295 , 400 






{» 


30 


C 


6,400 


7, 100 


N 
P 

N 
P 


10 
30 

30 
30 


c 


84,400 


Coe 


21, IOO 


F 


21, IOO 










\ C 


400, 




c 


21, IOO 


Coe 


21, IOO 


F 


42, 200 


















{* 


42, 200 


Coe 

S 


126,600 

2, IOO 


F 






2, IOO 



6o6 



BULLETIN OF THE BUREAU OF FISHERIES. 



Table XIX.— Analysis of Plankton Catches — Continued. 

HEMLOCK LAKE, AUG. 23, 1910. 



Depth, meters. 



Cladocera. 



Copepoda. 



Nauplii. 


Rotifera. 




Protozoa. 


Green and 

blue-green 

algae. 


Diatoms. 




An 


300 

4. 300 






Aph 42,200 


A 


738,500 


19,300 


P 


C 


1,055,000 


C 84, 400 
Coe 337,600 


* 

T 


147, 700 
42,200 


20,000 


C 
P 


100 
4,300 


c 


1,477,000 


C 42,200 
Coe 464. 200 


A 
F 
T 


1,266,000 
42,200 
126,600 


18,000 


C 
N 
P 


1,400 
2,800 
2,800 


c 


1,566,400 


C 42, 200 
Coe 295 , 400 


A 
F 
T 


970,600 
337,6oo 
126,600 


81,400 


C 

N 
P 
T 


700 

4,200 

700 

2, 100 


c 


1,645,800 


C 42, 200 
Coe 1, 097, 200 


A 
F 
T 


379,800 
337.600 
168,800 


50,700 


An 

N 


700 
700 


c 


844.000 


Coe 422,000 


A 
F 


126,600 
465.300 


57. 100 


N 


2, 100 


c 


633,000 


Coe 590, 800 


A 
F 


126,600 
84,400 


11,400 


T 


4.200 


c 


2X1, OOO 


Coe 717,400 


A 
F 


1,000 
168,800 



5 

8 

12... 

15... 
20. . . 
26... 



Di 



Id 

jDi 



SO 
7,800 
1,700 



D 5,000 

Di 500 

L 200 



5»7oo 
700 



1,000 
2, 100 



150 
150 



2,860 
2,500 



C 5,000 

D 2,800 



1,400 
1,400 



C 10, 700 
D 8,000 



2,800 
2,800 

3,600 
10,000 

700 

2,800 



KEUKA LAKE, AUG. 18, I9 io. 



25-30. 



650 
130 
130 
150 



260 
400 



130 
2,230 



260 
2,490 



260 
900 



130 
260 



130 
SO 



10,800 



17,000 



2.7SO 
260 
400 



260 
260 
520 



130 

4,060 



130 

7,900 



60 

2.750 



200 
1.230 



650 



An 
C 

N 
P 

An 
C 

N 
P 

An 

As 

C 

N 

P 

An 
As 
C 

N 
P 
T 

An 
C 

N 
P 
T 

An 
P 

T 

An 
P 

T 

N 
P 
T 



2,360 

200~ 
1,440 
18,300 

1,300 

I30 

2,230 

II,70O 

6,000 
260 
260 
40O 

4,300 

2,750 
4O0 
IOO 
I30 

3.I40 
I30 

1,300 
I30 
130 

7.700 
900 

65O 
9,7O0 

6so 

130 

3,200 

39o 

260 

910 



77.400 


7 


700 


286 


400 


224, 400 


38, 


700 


31 


OOO 


IS 


500 


11 


SOO 


11 


OOO 



C 

Coe 



C 

Coe 



Aph 
C 

Coe 
O 



Aph 
C 

Coe 
O 



Aph 

C 

O 



Aph 

C 

O 

Aph 

C 

O 

C 

o 



7 
7. 


700 

700 


1 


200 


X, 


IOO 


7,700 

7,700 

7,700 

77,400 


5 


OOO 


7. 


OOO 


S. 

835 


500 
900 


7 


OOO 


4 

3°i 


OOO 

800 


IS 
3 

154 


Soo 

OOO 

800 


1 
3 


500 

OOO 


23 


200 


5 
13 


500 
800 



619, 200 

IS. Soo 

866,900 

38, 700 

,153,200 

. 532, 500 

69,600 



A 921,000 
F 1,470,600 
T 433.400 



201, 200 
83s, 900 
681,000 



154,800 
425, 700 
317.300 



38,700 
263,200 
92,900 

34,800 
50,300 
31,000 

107,600 
8s,Soo 
27,600 



A LIMNOLOGICAL STUDY OF THE FINGER LAKES. 



607 



Table XIX. — Analysis of Plankton Catches — Continued. 

OTISCO LAKE, AUG. 16, 1910. 



Depth, meters. 



6-9. 



Cladocera. 



I 



{■> 



2,830 

1,850 

6s 



[D 2,000 

Di 1,100 
L 30 



Copepoda. 



13.860 

5-350 



10,500 
6, 550 



1,500 
27,300 



260 
650 



Nauplii. 



13,860 



6,150 



Rotifera. 



An 650 

N 220 

P 7, 53o 

An 500 

N 210 

P 10, 500 



An 
P 



1, 260 
5.900 



Protozoa. 



148,800 



235,600 



24,800 



15,400 



Green and 
blue-green 

alga. 



C 

Coe 



C 

Coe 

C 
Coe 



C 
Coe 



49,600 
43,400 



272,800 
260, 400 

24,800 
148,800 



7,700 
27,000 



Diatoms. 



24,800 
6,200 



C 37,200 

F 37, 200 

M 12,400 



86,800 
49,600 

7,700 
7.700 
23, 200 
3.900 



OWASCO LAKE, AUG. 13, 1910. 



5 

[Di 


3.400 
130 
400 


C 
D 


780 
1,700 


5. 

[Di 


920 
400 
920 


C 
D 


3.800 
4,200 


s 

Di 


400 

1,560 

400 


C 
D 


400 

6,700 


fB 


50 


D 


13,000 


ID 


130 


K 


200 



10,600 



6, 700 
400 



3,800 
130 



13,800 

3.400 

5.200 
3.000 

1,200 

1,700 
650 
780 
520 



As 
P 


1.830 
9.560 


As 

C 

P 


700 

260 

11,800 


C 
P 


130 
650 


P 


520 


P 


130 


P 


130 


P 


100 


P 


130 


P 


50 



54,200 
I, 269,000 



31,000 

1.470.600 



65,800 



500 
46,400 

34,800 



D 


50,300 


D 


23,200 


D 


27,100 


D 


30,900 



c 

G 

An 

Aph 

C 

An 

Aph 

C 

Aph 
C 

Aph 
C 

Aph 

C 

O 

Aph 
C 

Aph 
C 

Aph 
C 



46, 700 
7,700 



7,700 
38,700 
62,000 

3.800 
15.S00 
27, 100 

23. 200 
3,800 

7,700 
it, 600 

27,000 
15.500 
3,800 

23,200 
3.800 

15.500 
3.800 

15.500 
3,800 

3.800 



500 
700 
500 

7.700 
7.700 



3,800 

7.700 
7,700 



SENECA LAKE, AUG. 4, 1910. 





p 


800 


c 


2,500 


1,250 


An 
As 
PI 
P 


1,250 

400 

3.300 

18,000 


c 

V 


36,900 
4, 100 


c 


7.700 


A 
T 


98,400 




•2,300 














An 


7,000 
















{? 


II,2SO 
400 


C 


3.750 


8,750 


As 
N 
PI 


2,500 
800 

5,000 


c 


24,600 


A 

C 


24,600 
10,000 


A 
T 


86,000 




12,300 














P 


31,600 
















1° 


18,000 


C 


1,600 


11,250 


An 
As 
P 


3. 7SO 
I,2SO 

20,800 


c 


98.400 


c 


17.300 


A 
F 

T 


233.700 
24,600 
12,300 





6o8 



BULLETIN OF THE BUREAU OF FISHERIES. 
Table XIX. — Analysis op Plankton Catches — Continued. 



SENECA LAKE, AUG. 4, 1910— Continued. 



Depth, meters. 



Cladocera. 



Copepoda. 



Nauplii. 



Rotifera. 



Protozoa. 



Green and 

blue-green 

algae. 



Diatoms. 



15 

20..... 

50...... 

SO-7S--. 
7S-ioo. 

100-130 
130-165 

0-10. ... 

10-20. . , 
30-30.., 

30-50... 

50-70... 
70-80... 



B 24, 100 



B 7,100 



B 1,650 



B 25 



c 


15,800 


D 


5; OOO 


c 


20,000 


D 


8,000 


c 


20,000 


D 


20,000 


C 
D 


50 
820 


1 


50 
250 
30 


IE 


40 

loo 


II 


20 


fC 


20 


ID 


ISO 



68, 300 



280 



An 

As 

C 

N 

P 

An 

N 

P 

An 
P 



An 
P 



An 
P 



An 
P 



An 
P 



1,250 

400 

1,000 

I>2SO 

22, IOO 

I.2SO 
I,2SO 

3>750 

200 
3> 000 



30 
130 



C 24,600 



C 12,300 



500 



600 



C 16,000 



A. 1,350,400 
F 12,300 
T 12,300 



A 332,000 
E 36,900 

T 12,300 



Soo 



500 



61, 500 

1,000 

500 



A 1,000 

F 250 

T 250 



850 



IOO 

500 



SKANEATELES LAKE, AUG. 15, 1910. 



■ 


1,000 


C 
D 


460 
4,400 


§ 


190 
400 
190 


C 
D 

C 


14 


260 
700 

60 


1 D 


60 


D 
L 


2 


,600 
60 


B 


10 
30 


D 
L 




430 
30 


B 


10 


D 
L 

/ D 
\L 




120 
60 

60 

IOO 



As 400 

C 60 

P 460 



1,700 

2,360 
1,860 



250,900 
7,700 



9,600 

3> 800 

3, 860 



An 

C 

G 

An 
Ap 
C 
Coe 

An 

C 

Coe 

C 

Coe 

Coe 



C 
Coe 



50, 200 
19,300 
15,400 

54,200 
30,900 
3.800 
3,800 

7,700 

I, IOO 

900 

400 
400 



150 

IOO 



220,000 
3.800 
7,700 

108,000 



4,092,000 
11,600 



A 2, 146, 000 
S 54, 000 



1, 162,000 

1,900 

21, 200 

331,000 
5,800 

127,400 
IS. 400 



A LIMNOEOGICAE STUDY OF THE FINGER LAKES. 
TRANSPARENCY. 



609 



The transparency of the water was determined in 1910 by means oT a Secchi's disk about 10 centi- 
meters in diameter. The depth at which this disk disappeared from view was as follows: 

Table XX. — Transparency of Water. 



Lakes. 


Trans- 
parency. 


Lakes. 


Trans- 
parency. 




Meters. 
4.0 
3-7 
5-i 
6.3 


Hemlock 


Meiers. 






3-° 
8.3 
10.3 




Seneca 











OXYGEN ABSORPTION. 

Table XXI. — Number of Cubic Centimeters of Oxygen Absorbed by i Liter of Distilled 
Water at Diffreent Temperatures from a Free Dry Atmosphere of 760 mm. Pressure. 



Temp. 


O 


1 


2 


3 


4 


5 


6 


7 


8 


9 


— 2 


IO. 880 


10. 850 


10. 820 


10. 790 


10. 760 


10. 730 


10. 700 


10.670 


io. 640 


10. 610 


— 1 


IO.580 


10.551 


10. 522 


IO- 493 


10. 464 


IO-435 


10.406 


10-377 


10. 348 


10.319 





10. 290 


10. 263 


10. 236 


IO. 209 


10. 182 


10. 155 


10. 128 


IO. 101 


10. 074 


10. 047 


1 


10. 020 


9-993 


9.966 


9-939 


9.912 


9.885 


9-858 


9.831 


9.804 


9-777 


2 


9- 7SO 


9-725 


9. 700 


9-675 


9-650 


9.62s 


9.600 


9-575 


9- S5o 


9-525 


3 


9. 500 


9-476 


9-452 


9.428 


9.404 


9-38o 


9-356 


9-332 


9-308 


9.284 


4 


9- 260 


9-237 


9.214 


9. 191 


9.168 


9-145 


9. 122 


9.099 


9.076 


9- 053 


S 


9-030 


9-008 


8.986 


8.964 


8.942 


8.920 


8.898 


8.876 


8.854 


8.832 


6 


8.810 


8.789 


8.768 


8.747 


8.726 


8.705 


8.684 


8.663 


8.642 


8.621 


7 


8.600 


8.580 


8.560 


8.54° 


8. 520 


8. 500 


8.480 


8.460 


8.440 


8.420 


8 


8.400 


8.381 


8.362 


8-343 


8.324 


8.305 


8.286 


8.267 


8.248 


8. 229 


9 


8. 210 


8. 191 


8. 172 


8-153 


8.134 


8. 115 


8.096 


8.077 


8.058 


8.039 


10 


8.020 


8.002 


7-984 


7.966 


7-948 


7-930 


7.912 


7.894 


7-876 


7.859 


11 


7.840 


7.824 


7.808 


7-792 


7-776 


7. 760 


7-744 


7.728 


7.712 


7.696 


12 


7.680 


7.664 


7-648 


7.632 


7.616 


7. 600 


7-584 


7-568 


7-542 


7.526 


'3 


7-520 


7-505 


7-490 


7-475 


7-460 


7-445 


7- 430 


7-415 


7.400 


7-38S 


14 


7-37° 


7-35S 


7- 340 


7-325 


7- 3io 


7.295 


7.280 


7.265 


7.250 


7- 23s 


IS 


7.220 


7. 206 


7.192 


7.178 


7-164 


7-ISO 


7-136 


7. 122 


7.108 


7.094 


16 


7.080 


7.066 


7.052 


7.038 


7.024 


7.010 


6.996 


6.982 


6.968 


6.954 


17 


6. 940 


6.927 


6.914 


6.901 


6.888 


6-87S 


6.862 


6.849 


6.836 


6.823 


18 


6.810 


6.798 


6.786 


6.774 


6. 762 


6.750 


6.738 


6. 726 


6.714 


6. 702 


19 


6.690 


6.678 


6.666 


6.654 


6.642 


6.630 


6.618 


6.606 


6.594 


6.582 


20 


6.570 


6-559 


6.548 


6-S37 


6.526 


6-515 


6.504 


6-493 


6.482 


6.471 


21 


6.460 


6.449 


6.438 


6.427 


6. 416 


6.405 


6-394 


6-383 


6.372 


6.361 


22 


6.350 


6-339 


6.328 


6-317 


6.306 


6.29s 


6.284 


6.273 


6. 262 


6. 251 


23 


6. 240 


6. 230 


6. 220 


6. 210 


6. 200 


6. 190 


6.180 


6. 170 


6. 160 


6. 150 


24 


6. 140 


6.130 


6. 120 


6. no 


6. 100 


6. 090 


6.080 


6-070 


6. 060 


6.050 


»S 


6.040 


6.030 


6.020 


6.010 


6.000 


5-990 


5.980 


5- 970 


5-960 


S-950 


26 


5-94° 


5- 930 


5.920 


5.910 


5-900 


5.890 


5.880 


5.870 


5- 860 


5-8so 


27 


5-840 


5-831 


5.822 


5- 813 


5.804 


5-795 


5-786 


5-777 


5-768 


5-759 


28 


5- 750 


5-741 


5-732 


5-723 


5-714 


S-7os 


5-696 


5.687 


5. 678 


5.669 


29 


5.660 


5-651 


5-542 


5-633 


5.624 


5-6IS 


S.606 


S-597 


S-588 


5-579 


3° 


S-S70 


5-56I 


5-552 


5-543 


S-534 


S-S25 


S-SI6 


5-507 


5-498 


S-489 



Bull. U. S. B. F., 1912 



OTISCO AND SKANEATELES LAKES 

(UPPER, SMALLER LAKE IS OTISCO) 

Topography from maps of the United States Geological Survey. 1902 

Hydrography from survey by Cornell University 
(Skaneateles, 1893 ; Otisco. 1897) 




Hull. U. S. B. F.. 1H12 



Plate CXII 



OWASCO LAKE 

Topography from maps ol the United Stales Geological Survey. 1909 
Hydrography from survey by Cornell University. 1896-1897 




P OCIY 




BULL. l T - S. B. F., 1912 




Bull. U. S. B. P., 1912 



Plate CXVI 




X 



LC \ D '15 



UBRMwSSSi • 



029 7141636 



